Tactics for playing as the Sylvan faction.

Summoned a phoenix and earth elementals, and the elves were dying one after another, while the phoenix didn't even flinch: it has 800+ hit points and takes minimal damage – from 0 to 20, depending on the strength of the attacking creature. The elves can't do that.

In late-game scenarios with large armies, phoenixes, and even more so, elementals, don't play a significant role anymore. The elves certainly can't do that, but they have light magic, which greatly enhances their already very strong and fast troops. 3 mini-arts are compensated by 3-4 blessed creatures, elven luck, and the weak defense and attack of the mage hero himself. In my experience, mages are not the most serious opponent for elves in the late game; I am much more wary of orcs and undead, but this is just my personal opinion.