Absolute skills

A Mentor is a rare and expensive asset in Tactical Edition. Each skill reset after 5 attempts consumes an entire turn. Based on experience playing on TE mode, the most useful super ability for Elves is... however, in recent versions, the skill tree has been made more complex, and I haven't seen it used in a while.
Contact with opponents usually occurs around levels 20-25. It's rare for a game to drag on into a late game, and heroes rarely reach levels 28+.