You feel the power of Zeus running through your body as you grasp the javelin in your hand ready to take aim and destroy your enemies.  As long as this weapon is attuned to you, it will always return to your side.

Call Lightning:  Cast at level 6

A storm cloud appears in the shape of a cylinder that is 10 feet tall with a 60-foot radius, centered on a point you can see within range directly above you. The spell fails if you can't see a point in the air where the storm cloud could appear (for example, if you are in a room that can't accommodate the cloud).

When you cast the spell, choose a point you can see under the cloud. A bolt of lightning flashes down from the cloud to that point. Each creature within 5 feet of that point must make a Dexterity saving throw. A creature takes 6d10 lightning damage on a failed save, or half as much damage on a successful one. On each of your turns until the spell ends, you can use your action to call down lightning in this way again, targeting the same point or a different one.
If you are outdoors in stormy conditions when you cast this spell, the spell gives you control over the existing storm instead of creating a new one. Under such conditions, the spell's damage increases by 1d10.

Chain Lightning:  Cast at level 6

You create a bolt of lightning that arcs toward a target of your choice that you can see within range. Three bolts then leap from that target to as many as three other targets, each of which must be within 30 feet of the first target. A target can be a creature or an object and can be targeted by only one of the bolts.

A target must make a Dexterity saving throw. The target takes 10d8 lightning damage on a failed save, or half as much damage on a successful one.

Lightning Bolt:  Cast at level 6

A stroke of lightning forming a line 100 feet long and 5 feet wide blasts out from you in a direction you choose. Each creature in the line must make a Dexterity saving throw. A creature takes 11d6 lightning damage on a failed save, or half as much damage on a successful one.
The lightning ignites flammable objects in the area that aren't being worn or carried.

Proficiency with a Javelin allows you to add your proficiency bonus to the attack roll for any attack you make with it.

Notes: Disadvantage: Ability Checks, Exhaustion, follower of Zeus, Damage, Combat, Thrown, Slow