He didn’t bat an eye seeing his own bodies piling up, so although the shared glee of both of him at the end makes perfect sense, it’s clearly a scene of utter madness. He can only see his goal. The clone accepted his fate because he understood he was the clone, and only his understanding of this meant that he succeeded.
Trying to find who would represent that doomed role in Yuuma’s story…would that be Yuuma? No matter how the end looks, if Yuuma brings his goal to fruition, will he push to convince himself that it’s fine because otherwise he would have to accept the whole thing as a failed tragedy that he caused?