- Heroes in Heroes 3

2 Sasha CAA
Sir Mullich gains Wisdom at level 6. You can check this.

There are no strict rules for the appearance of a specific secondary skill (if it can appear at all, of course). There are only some dependencies and probabilities. For Sir Mullich, there is a high probability of the skill appearing when reaching Level 6, but not 100%.

In general, the probability of Wisdom appearing for Knights is only 3%. Only Barbarians, Beastmasters, and Wanderers have a lower probability (they have 2%). So, indeed, Wisdom rarely appears for them. The tree of secondary skills for each hero is formed at the very beginning of the game according to some unknown laws. This is a very mysterious matter...