Summary for Ep 43 in official websites:
Lost Ankh is defeated, Ankh appears again in front of everyone. But, after getting his Cores broken because of OOO, Ankh needs to use Shingo's body again.
'Leave Shingo's body and return it to Hina!'
Eiji is strangely furious and threats to use the purple medals to fight Ankh. But Ankh still possessed Shingo and escapes.
Ankh is lacking of Cores, becoming complete is even harder than before, he approaches Dr. Maki who is turning into a Greeed. Maki gives him a suggestion, what is it...?
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In Ep 42, Maki explained to Eiji that Greeeds have the desire to become human, that want to have the five senses. Both of them are incomplete, hence their lack of senses. When a Greeed becomes complete, they will look at the world like humans do. Furthermore if they go berserk, their power is enough to swallow the whole world into darkness. This is what Maki is wanting, the 'perfect end'.