Who has enough powerful magic.

Something is off. There are no Berserkers or other high-level creatures in the guild, for example. Relying on castles isn't a good idea. Everyone has low-level spells. And for the Sylvan elf, the summoning spell is almost useless. Only Phantom is somewhat helpful. Everything else heavily depends on magic. Phoenix will be weak, there will be few elementals, and so on.