About

The magician is a powerful magical hero, who prefers using magic over using brute force.
double mana regeneration
+25% resistance to spells

Strategy

Have your land at approximately 75% mines, and 25% amplifiers. Spend hero points on only mana. Spell power increases will never be sufficient to make up for the loss in mana. When building troops, don't mess with knights or pikeman, go straight for the relatively cheap elites. Try to keep as many troops as you can so your income as low as possible (but still positive), and use your mana in alchemy 3 times every 5 hours (instead of 3 times every 10 hours like the other classes). Then just use physical attacks to grow and gain experience.

If as a magician you get chained by a larger army than you, you have the advantage of pouring a rain of fireballs on them until you can physically defeat them. If you put all of your mana into the fireballs, it won't take long to seriously decimate their forces.