Help with a champion concept

I'm working on a champion concept that is basically a beefy melee mage, and I have most of the abilities down, but I need help with coming up with an E

Passive - can not be affected by Movement impairing Hard CC (stun, root, snare, charm, fear, knock up) for longer than 1.15 second

Q - holds 2 charges and has 2 second cast casting cooldown between charges, spend a charge to deal AOE damage in a 180 degree cone in the chosen direction, each cast has 40% chance to heal you by 30% of damage dealt Ability damage scales with AP

E - killing minions stores charges (max 5) at max charges you can cast the ability, your next AA deals bonus on hit magic damage and summons the 5 minions You killed as ally minions, these 5 minions are slightly beefier and stronger but reward enemies that kill them double gold On hit Damage scales off AP

R - gain a physical Damage shield, bonus AP and 15% MS Shield scales with AP

Anyone have any ideas for an E that compliments this kit?