Zagan be like:
Well, since there'll be more of those who'd interfere/bother us (other fellow Archdemons and sorcerers mainly; etc.) than guests ('Orias'/Nephy's mother; the neighboring Knight Order that Chastille leads; Barbatos; Nephteros; etc.).
Might as well bestow my most trusted, a boon, and see how those that'd intrude/interfere more often, to get taught some more lessons upon them and then some.
Also Zagan: pg.9-10
I also wouldn't want to interfere between you both since you both have been partners together for quite a long time