Mid-game is where most of my characters die. If it wasn't for stone block traps and other such RNG fuck-overs, anyone with enough caution can survive the early game.
Beastfighters are insanely powerful at high levels because of their scaling damage but this means that you are also limited by this. Gaining levels fast is pretty important for a beastfighter but for the most part, their damage is on par with what is needed for their level. Sadly, lots of ultra-tough melee characters like beastfighters and barbarians get so set into being so ultra-tough that they don't train any of their missile skills and entirely ignore using wands and such because they have an unlimited resources of damage in their hands. But once these powerhouses reach mid-game, there are several monsters who can put them in their place and remind them that all ADOM characters are mere mortals.
Don't be shy of death, just learn from each one and think of new strategies to avoid that death. Eventually, you will die enough times to learn enough lessons that one day when the RNG isn't at its ultimate evilness (or you are just that prepared and chicken out of every single dangerous encounter until you can defeat it) that you get a win easily. There's a lot of things that you won't know until you beat the game, such as how much corruption a PC really can take. I used to be so scared of corruption that I thought I would always turn into some mass of purple until I finally beat the game (on a crowned C beastfighter actually) and realized that you can work around corruptions (I had poison hands most of the game which was awesome for the extra damage on bosses and tough monsters but I can vividly remember having a huge stack of poisons after picking up my gear from an altar b/u/c id...)
I said it before, and I'll say it again. If I knew scripture like you, I'd prolly be an athiest too.. -gut
/l、
(゚、 。 7
l、 ~ヽ
じしf_, )ノ