As a fellow Ron Warlock, Romand should be very clear about Xu Nan's current predicament.
The strategy of using a substitute was excellent. Although it wasn't put to use, it was because Xu Nan had discovered an even better shortcut.
And this time around, the reason why he allowed Xu Nan to participate in the Aurora tide was to make up for the weakness of warlocks in terms of magic power.
From the start, Xu Nan rarely had situations where he ran out of mana. Firstly, it was because of the existence of fate power, which allowed him to have other sources of energy.Secondly, he didn't participate in enough battles. Most of them could be settled in one go, and there were very few battles that lasted.
However, he was indeed lacking in magic power.