Helen Summoned (Patreon)

Got this one from Chien for Helen's summoning CG. The Chromatic Elves and Helen being summoned may be confusing, since they are in the same realm as the player is in. 

Basically, Summoning will both serve as a way to get new characters, but also strengthen existing harem members by acquiring alternate universe versions of them and using them to strengthen the harem member. "Local" characters will still be obtained without summoning them, but they can also be summoned and strengthened.