Hilde : E Commit: Your attack gets +X damage and +X speed. X equals double the amount your attack's damage was reduced by during the Enhance Phase.

E: Your attack gets -1 damage and -1 speed. If your attack deals damage, draw 1 card.

Lightning Horn : E: If this attack's damage is less than its printed damage, it gets Powerful: 2.

Combo E: This attack gets +X damage. X equals double the amount that this attack's damage was reduced by during this Enhance Phase.

My question is, lets say i play Lightning Horn..and i used Amy's Assistance to give it..-5 damage. Then i use Hilde to give it an additonal -1. -6 Total. If i then use Hilde's Enhance Commit to boost the damage and speed, will the combo enhance on Lightning Horn still remember that "hey, i got reduced by 6 damage earlier, even though i was just given +12 +12" and still be playable for an additonal +12 damage?

absolutely, it say "during this enhance phase"

so yes

Stamp for Cass. All reductions will be tallied.

Though in your scenario i would remember to give it powerful 2 before you pump it up (just incase you need it with your attack at a mere 22 damage), as that enhance is only playable while it is below its printed.

Yea Obviously, heh, Powerful 2 is teh hotness