diff --git a/packages/entity/src/behavior-components/expression.jsx b/packages/entity/src/behavior-components/expression.jsx
index 20f4f63..70835f5 100644
--- a/packages/entity/src/behavior-components/expression.jsx
+++ b/packages/entity/src/behavior-components/expression.jsx
@@ -1,7 +1,11 @@
 import {join, relative} from 'path';
 
-import {isInvocation, isKey} from '@avocado/behavior';
-import {PropTypes, React} from '@latus/react';
+import {compile, isInvocation, isKey} from '@avocado/behavior';
+import {
+  PropTypes,
+  React,
+  useLatus,
+} from '@latus/react';
 import {useJsonPatcher} from '@persea/json';
 import classnames from 'classnames';
 
@@ -10,18 +14,18 @@ import Key from './expression/key';
 
 const Expression = ({
   context,
-  expression,
+  value,
   path,
   type,
 }) => {
+  const latus = useLatus();
   const patch = useJsonPatcher();
   let i = 0;
-  const {ops} = expression;
+  const {ops} = value;
   const Renderables = [];
   let opsCount = 0;
-  let walk = context;
   // eslint-disable-next-line react/destructuring-assignment
-  let description = context.constructor.descriptionFor(walk);
+  let description = context.constructor.descriptionFor(context);
   const onChange = (event, value, localPath) => {
     const patches = [];
     const j = parseInt(relative(path, localPath).split('/')[1], 10);
@@ -100,8 +104,8 @@ const Expression = ({
               onChange(event, value, localPath);
             }
           }}
-          op={op}
           path={opPath}
+          value={op.key}
         />,
       );
       opsCount += 1;
@@ -136,15 +140,10 @@ const Expression = ({
       opsCount += 1;
     }
     if (isKey(op)) {
-      if (context === walk) {
-        [walk] = context.get(op.key);
-      }
-      else {
-        walk = walk[op.key];
-      }
+      const current = compile({type: 'expression', ops: ops.slice(0, i + 1)}, latus)(context);
       description = {
-        ...context.constructor.descriptionFor(walk),
-        ...description.children[op.key],
+        ...context.constructor.descriptionFor(current),
+        ...description?.children?.[op.key] || {},
       };
       if (description.args && (!nextOp || !isInvocation(nextOp))) {
         Renderables.push(
@@ -154,17 +153,16 @@ const Expression = ({
             onClick={((description, opPath) => () => {
               const parts = opPath.split('/');
               parts.push(parseInt(parts.pop(), 10) + 1);
-              const invocation = {
-                type: 'invoke',
-                args: description.args.map(() => ({
-                  type: 'literal',
-                  value: null,
-                })),
-              };
               patch({
                 op: 'add',
                 path: parts.join('/'),
-                value: invocation,
+                value: {
+                  type: 'invoke',
+                  args: description.args.map(() => ({
+                    type: 'literal',
+                    value: null,
+                  })),
+                },
               });
             })(description, opPath)}
             type="button"
@@ -218,7 +216,7 @@ Expression.propTypes = {
     describe: PropTypes.func,
     get: PropTypes.func,
   }).isRequired,
-  expression: PropTypes.shape({
+  value: PropTypes.shape({
     ops: PropTypes.arrayOf(
       PropTypes.shape({
         key: PropTypes.string,
diff --git a/packages/entity/src/behavior-components/expression/invocation.jsx b/packages/entity/src/behavior-components/expression/invocation.jsx
index 010c087..808de71 100644
--- a/packages/entity/src/behavior-components/expression/invocation.jsx
+++ b/packages/entity/src/behavior-components/expression/invocation.jsx
@@ -1,22 +1,33 @@
 import {join} from 'path';
 
 import {PropTypes, React} from '@latus/react';
-import {useJsonPatcher} from '@persea/json';
 
-import Literal from '../literal';
-import Key from './key';
+import Variant from '../variant';
 
 const Invocation = ({
   context,
   description,
-  Expression,
   onChange,
   op,
   path,
 }) => {
   // eslint-disable-next-line react/destructuring-assignment
-  const contextDescription = context.describe();
-  const patch = useJsonPatcher();
+  const argComponent = (arg, i) => {
+    const argPath = join(path, 'args', i.toString());
+    const options = description?.args?.[i].options;
+    const type = description?.args?.[i].type || 'undefined';
+    return (
+      <Variant
+        context={context}
+        onChange={onChange}
+        op={op}
+        options={options}
+        path={argPath}
+        type={type}
+        value={arg}
+      />
+    );
+  };
   return (
     <div className="invocation">
       (
@@ -26,55 +37,7 @@ const Invocation = ({
             key={join(path, 'args', i.toString())}
             className="invocation__arg"
           >
-            {
-              'literal' === arg.type
-                ? (
-                  <>
-                    <Key
-                      childrenDescription={{
-                        '<literal>': {
-                          label: '',
-                          type: arg.type,
-                        },
-                        ...contextDescription.children,
-                      }}
-                      onChange={(event, value) => {
-                        patch({
-                          op: 'replace',
-                          path: join(path, 'args', i.toString()),
-                          value: {
-                            type: 'expression',
-                            ops: [
-                              {
-                                type: 'key',
-                                key: value,
-                              },
-                            ],
-                          },
-                        });
-                      }}
-                      op={op}
-                      path={path}
-                    />
-                    <Literal
-                      onChange={onChange}
-                      options={description.args[i].options}
-                      path={join(path, 'args', i.toString(), 'value')}
-                      type={description.args[i].type}
-                      value={arg}
-                    />
-                  </>
-                )
-                : (
-                  <Expression
-                    context={context}
-                    expression={arg}
-                    onChange={onChange}
-                    path={join(path, 'args', i.toString())}
-                    type={description.args[i].type}
-                  />
-                )
-            }
+            {argComponent(arg, i)}
             {i < op.args.length - 1 && <span className="invocation__arg-sep">, </span>}
           </div>
         ))
@@ -85,9 +48,7 @@ const Invocation = ({
 };
 
 Invocation.propTypes = {
-  context: PropTypes.shape({
-    describe: PropTypes.func,
-  }).isRequired,
+  context: PropTypes.shape({}).isRequired,
   description: PropTypes.shape({
     args: PropTypes.arrayOf(
       PropTypes.shape({
@@ -96,7 +57,6 @@ Invocation.propTypes = {
       }),
     ),
   }).isRequired,
-  Expression: PropTypes.func.isRequired,
   onChange: PropTypes.func.isRequired,
   op: PropTypes.shape({
     args: PropTypes.arrayOf(PropTypes.any),
diff --git a/packages/entity/src/behavior-components/expression/key.jsx b/packages/entity/src/behavior-components/expression/key.jsx
index 9da4b9d..739025f 100644
--- a/packages/entity/src/behavior-components/expression/key.jsx
+++ b/packages/entity/src/behavior-components/expression/key.jsx
@@ -5,8 +5,8 @@ import {PropTypes, React} from '@latus/react';
 const Key = ({
   childrenDescription,
   onChange,
-  op,
   path,
+  value,
 }) => {
   const options = Object.entries(childrenDescription)
     .map(([key]) => (
@@ -18,7 +18,7 @@ const Key = ({
         onChange={(event) => {
           onChange(event, event.target.value, join(path, 'key'));
         }}
-        value={op.key}
+        value={value}
       >
         {options}
       </select>
@@ -29,10 +29,8 @@ const Key = ({
 Key.propTypes = {
   childrenDescription: PropTypes.shape({}).isRequired,
   onChange: PropTypes.func.isRequired,
-  op: PropTypes.shape({
-    key: PropTypes.string,
-  }).isRequired,
   path: PropTypes.string.isRequired,
+  value: PropTypes.string.isRequired,
 };
 
 export default Key;
diff --git a/packages/entity/src/behavior-components/expressions.jsx b/packages/entity/src/behavior-components/expressions.jsx
index 4030561..4bdf955 100644
--- a/packages/entity/src/behavior-components/expressions.jsx
+++ b/packages/entity/src/behavior-components/expressions.jsx
@@ -6,7 +6,7 @@ import Expression from './expression';
 
 const Expressions = ({
   context,
-  expressions: {expressions},
+  value: {expressions},
   path,
 }) => (
   <div className="expressions">
@@ -14,7 +14,7 @@ const Expressions = ({
       expressions.map((expression, i) => (
         <Expression
           context={context}
-          expression={expression}
+          value={expression}
           key={join(path, 'expressions', i.toString())}
           path={join(path, 'expressions', i.toString())}
           type="void"
@@ -26,7 +26,7 @@ const Expressions = ({
 
 Expressions.propTypes = {
   context: PropTypes.shape({}).isRequired,
-  expressions: PropTypes.shape({
+  value: PropTypes.shape({
     type: PropTypes.string,
     expressions: PropTypes.arrayOf(
       PropTypes.shape({}),
diff --git a/packages/entity/src/behavior-components/literal.jsx b/packages/entity/src/behavior-components/literal.jsx
index e210c7c..44e3123 100644
--- a/packages/entity/src/behavior-components/literal.jsx
+++ b/packages/entity/src/behavior-components/literal.jsx
@@ -1,17 +1,29 @@
+import {join} from 'path';
+
 import {PropTypes, React} from '@latus/react';
 import {
   Number,
 } from '@persea/core';
-import {JsonComponent} from '@persea/json';
+import {
+  JsonComponent,
+  useJsonPatcher,
+} from '@persea/json';
+
+import Key from './expression/key';
 
 const Literal = ({
+  context,
   onChange,
   path,
   type,
+  op,
   options,
-  value: {value},
+  value,
 }) => {
-  const valueComponent = (path, type, value) => {
+  // eslint-disable-next-line react/destructuring-assignment
+  const contextDescription = context.describe();
+  const patch = useJsonPatcher();
+  const valueComponent = (path, type, {value}) => {
     switch (type) {
       case 'number':
         return (
@@ -19,7 +31,7 @@ const Literal = ({
             onChange={(event, value) => {
               onChange(event, value, path);
             }}
-            value={value}
+            value={null === value ? 0 : value}
           />
         );
       case 'string':
@@ -29,7 +41,7 @@ const Literal = ({
             onChange={(event) => {
               onChange(event, value, path);
             }}
-            value={value || ''}
+            value={null === value ? '' : value}
           />
         );
       case 'object':
@@ -38,7 +50,7 @@ const Literal = ({
             onChange={(event, value) => {
               onChange(event, value, path);
             }}
-            json={value}
+            json={null === value ? {} : value}
           />
         );
       default:
@@ -46,32 +58,58 @@ const Literal = ({
     }
   };
   return (
-    <div className="literal">
-      {
-        options.length > 0
-          ? (
-            <select
-              onChange={(event) => {
-                onChange(event, value, path);
-              }}
-              value={options.findIndex(({value: optionValue}) => value === optionValue)}
-            >
-              {
-                Object.entries(options)
-                  .map(([key, {label}]) => (
-                    <option
-                      key={label}
-                      value={key}
-                    >
-                      {label}
-                    </option>
-                  ))
-              }
-            </select>
-          )
-          : valueComponent(path, type, value)
-      }
-    </div>
+    <>
+      <Key
+        childrenDescription={{
+          '<literal>': {
+            label: '',
+            type: value.type,
+          },
+          ...contextDescription.children,
+        }}
+        onChange={(event, value) => {
+          patch({
+            op: 'replace',
+            path,
+            value: {
+              type: 'expression',
+              ops: [
+                {
+                  type: 'key',
+                  key: value,
+                },
+              ],
+            },
+          });
+        }}
+        op={op}
+        path={path}
+      />
+      <div className="literal">
+        {
+          options.length > 0
+            ? (
+              <select
+                onChange={onChange}
+                value={options.findIndex(({value: optionValue}) => value.value === optionValue)}
+              >
+                {
+                  Object.entries(options)
+                    .map(([key, {label}]) => (
+                      <option
+                        key={label}
+                        value={key}
+                      >
+                        {label}
+                      </option>
+                    ))
+                }
+              </select>
+            )
+            : valueComponent(join(path, 'value'), type, value)
+        }
+      </div>
+    </>
   );
 };
 
@@ -80,8 +118,14 @@ Literal.defaultProps = {
 };
 
 Literal.propTypes = {
+  context: PropTypes.shape({
+    describe: PropTypes.func,
+  }).isRequired,
   type: PropTypes.string.isRequired,
   onChange: PropTypes.func.isRequired,
+  op: PropTypes.shape({
+    key: PropTypes.string,
+  }).isRequired,
   options: PropTypes.arrayOf(PropTypes.any),
   path: PropTypes.string.isRequired,
   // eslint-disable-next-line react/forbid-prop-types
diff --git a/packages/entity/src/behavior-components/variant.jsx b/packages/entity/src/behavior-components/variant.jsx
new file mode 100644
index 0000000..40961d1
--- /dev/null
+++ b/packages/entity/src/behavior-components/variant.jsx
@@ -0,0 +1,30 @@
+import {
+  PropTypes,
+  React,
+  useLatus,
+} from '@latus/react';
+
+const Variant = (props) => {
+  const {value} = props;
+  const {type} = value;
+  const latus = useLatus();
+  const BehaviorControllers = latus.get('%behavior-controllers');
+  const Controller = BehaviorControllers[type];
+  return (
+    <Controller
+      value={value}
+      // eslint-disable-next-line react/jsx-props-no-spreading
+      {...props}
+    />
+  );
+};
+
+Variant.propTypes = {
+  onChange: PropTypes.func.isRequired,
+  path: PropTypes.string.isRequired,
+  value: PropTypes.shape({
+    type: PropTypes.string,
+  }).isRequired,
+};
+
+export default Variant;
diff --git a/packages/entity/src/index.js b/packages/entity/src/index.js
index d5a1f41..b4f1153 100644
--- a/packages/entity/src/index.js
+++ b/packages/entity/src/index.js
@@ -2,6 +2,9 @@ import {basename, extname} from 'path';
 
 import {camelCase} from '@latus/core';
 
+import Expression from './behavior-components/expression';
+import Expressions from './behavior-components/expressions';
+import Literal from './behavior-components/literal';
 import EntityResourceController from './resource-controllers/entity';
 
 export {EntityResourceController};
@@ -11,6 +14,11 @@ export default {
     '@latus/core/starting': async (latus) => {
       const TraitRenderers = latus.invokeReduce('@persea/entity/trait-components');
       latus.set('%trait-components', TraitRenderers);
+      latus.set('%behavior-controllers', {
+        expression: Expression,
+        expressions: Expressions,
+        literal: Literal,
+      });
     },
     '@persea/core/resource-controllers': () => [
       EntityResourceController,
diff --git a/packages/entity/src/trait-components/alive.jsx b/packages/entity/src/trait-components/alive.jsx
index 7a18aaf..0937e05 100644
--- a/packages/entity/src/trait-components/alive.jsx
+++ b/packages/entity/src/trait-components/alive.jsx
@@ -14,7 +14,7 @@ const Alive = ({
       Death actions
       <Expressions
         context={entity.context}
-        expressions={json.params.deathActions}
+        value={json.params.deathActions}
         path={join(path, 'params/deathActions')}
       />
     </label>