Upon Danzel's late request, Agares decided to leave Shiro to sleep in their room while he went ahead to Danzel's room to watch over the runesmithing process.
Though it would be more convenient for him to simply give his sword to Danzel for the night, Agares went ahead and requested to watch from the side.
As for the reason, Danzel wasn´t too sure but he still accepted the old man's request.
His best guess was that either Agares didn´t trust him or that he treasured his sword too much to let others lay fingers on the scythe sword.
As for having his runesmithing secrets found out, Danzel didn´t worry too much. Although one could mimic the movement of his hand and also the symbol of the rune, the secret that made the rune work was a delicate control over mana, in an extremely specific way.