RTF is a global modification that replaces all towns in the game.

I also noticed a bug with the wisp's alt-upgrade (level 1 city upgrade during merging). Before the movement starts, the aura disappears, and the elven head just hangs in the air for 2 seconds. Then the aura reappears, and the wisp moves.

I think wisps look a bit out of place, so I suggest replacing them in the future with, say, Kabirs from Might and Magic VII! Why not? After all, many elementalists were former mages from the Silver Cities! Moreover, you could come up with interesting upgrades for this creature. Like: simple Kabir - fire Kabir - water Kabir (a Kabir that has learned another element... this can be quite logically explained!), or Kabir - Kabir Master - Kabir Wizard :D
What do you think?