1. What sort of build a battlemage should do. Ive read little bit about them and seen suggestions for both melee-based ones and caster based ones. Is the caster based one basically just wizard with heavy armor? What about the melee-based, im little confused about the attributes, is it something like max STR, around 10 INT with bonuses and rest CON and SPD? Im hoping people would suggest on attributes, talents and abilities. How well do hybrids work anyway, do they need alot of help from gear? Do you have to do alot of saving/loading for gear for it to work?
Decide if you want to do Melee or just be a Mage Tank. Start with 8 Str and 8 Int (with Know-It-All). The best battlemages are Aerotheurge (most powerful) or Pyromancy (lots of fun blowing everything up). If you want to focus on melee, raise Strength and leave Intelligence alone. If you want to focus on casting, raise Intelligence and leave Strength alone.
2. What talents would work for pure casters, seems Glass Cannon,Know-It-All,Far-out Man and Picture of Health atleast seem good, anything else? Does Know-It-All raise the max INT by 1, so you can later take 16 max or should you take it later when you have max INT so it raises the cap that way?
Lone Wolf, Glass Cannon, Know-It-All, Far-Out-Man, Elemental Affinity(unless you are Aerotheurge). Swift Footed is surprisingly handy along with Walk in Shadows and Fast Track if you want to pick up a tiny splash of Scoundrel.
I will ask some NB question too.
It is possible to play without melee character? How can i do it? I know that summon will help because NPC like summons but if will have ranger...
Yes, absolutely. One of the strongest combos in the game is a Ranger + Mage. There are lots of ways to do it, but I would recommend you shoot for a 5 Aerotheurge/1 Hydrosophist Mage and 5 Expert Marksman/1 Hydrosophist Ranger.
I still do not understand tenebrium. So, after some point i will be finding tenebrium weapons only? An they will be better than my crafted weapon?
Tenebrium weapons are inferior to Legendaries enhanced with Tenebrium bars. But either way, the moment you enhance a weapon with Tenebrium Bars it stops using your mundane weapon skills and uses your Tenebrium skill.
But you can win the game without putting anything into any weapon skills at all.