Multi-Role

Heroes can also choose between roles, but there is a cost for that versatility, while single roled heroes aquire habilities every level, multi-roled heroes aquire one hability for each role after 2 each levels.

That means that a tank-healer will have 2 tank and 2 healer abilities in level 1 but in level 2 only one tank ability and in level 3 only one healer ability and so on.