- Which faction is stronger? (Necropolis, Tower, or Conflux)

What about mages? After all, titans are considered the only monster equal in strength to the Black Dragons, and therefore stronger than both spectral dragons and phoenixes.

Titans are stronger than phoenixes in a 1v1 fight, but if you compare their weekly growth, I wouldn't envy the titans...
And in a duel between a Necromancer and a Tower, it really depends on the size of the map and the availability of resources.
Necromancers get dragons much earlier than Towers get titans.