But before joining people, Luciel just asked them to work together first as they're both linked with him, so they would be fighting side by side more than others.
They'll have to train to be used in cooperating with each other.
Of course, they don't really need to cooperate with each other after their abilities get stronger because it would probably be more effective if they fight on their own.
However, they should at least know how to cooperate with each other so that they'll develop some tacit understanding by seeing how the powers of each other work.
Unfortunately for him, he could only teach them for the time being, as he still couldn't use them properly and also couldn't cooperate with them because their strengths were still very low.
If he really let them join him then they'll just get in his way. Well, he would just let them watch how he fights so that they'll have some idea and think on how to cooperate with him in the future.
