Meanwhile, Irikaino composes a checklist.
If they had an Ainu around, they could build an Ainu-killing spell, even if they then went on to not use it against that particular test subject; but the magic refuses to give hints about how one might use it to kill a kind of being that has never existed in this world. So their best bet, if they ever need to fight a god, is for Serik to pick up a lot of power and start trying things on the spot until one of them works.
(Serik has not yet decided that he wants to go kill Melkor. Irikaino is pretty sure he is going to decide that he wants to go kill Melkor, but she's in no hurry to have that confirmed, because fighting gods is still dangerous no matter how troublesome the god, and in fact is arguably more dangerous precisely because this one is so troublesome. So they might as well take the time to prepare.)