The first level usually gets wiped out in the first few days while trying to break through something important. And then the game shifts to heroes and levels 3-4. The initial growth is roughly the same for everyone.
If we're talking about usefulness, then of course, it's the speed-boosting creatures and demons. Thieves are useful for gathering resources. Everything else is just junk for breaking through defenses and doesn't matter after the first week.
Не стремясь приобщиться к основам пришёл.
В прошлый раз утащил я молитвенный коврик,
Он истерся до дыр, - я за новым пришёл.
© О. Хайям