I play on impossible.
I don´t use any spells or any pet dragon skills, it is a truely solo, only Asmadeo.
The only problem is that you really need a few Walls from the pet dragon early when you don´t have any healskills. But if you have the heal at beginning on the round and the Vampireskill to regain health in melee combat you don´t need anyting later.
If you have luck and the more HP, Vampireskill and heal/round is early on the list to choose it should be 5-6 levels of Asmadeo to stopp walls from the pet dragon.
At the time now i have enough power and initiative that i teleport at the beginning of the first round near to the enemy and since i have 3 counters i barely have any health lost till round 2, only the enemy are half down
If there are really strong stacks i tease them a little (Speed 3 and the skill to avoid an attack are really nice).
I would tell that the skill to avoid an attack is to choose later on, because you teleport to an nearby random field after a avoid, if you are not strong it could be your death in no time.
More healing/round, more HP and more Vampirism should be the main picks at the early levels.
Damage reduction in melee is the next choice and later on the fire, poisen protection is a must have, but only if you would kill dragons. Dragons are later at the game and you should pick this skill also later. Then avoid attack and a new attack if you gain damage and if you made damage. I have maxed them all and i have if i are lucky 3 or 4 attacks in one round.
I have only one skeleton each round because the fight don´t start. In the beginning it is good to keep it alive to level the undead heal spell a little, but it go slowly because you can get all other skills in no time to level 20 and the heal undead is on level 2 or 3.
The skeleton dies also quickly. It is no need to level up with the healspell, later on when you have the Necromancer at level 3 you can heal yourself and level faster, but i have the skill now on level 7 and all other skills are beyound 40....you can skip this skill really, it is to slow to levelup.
Example, i get with a critical melee attack 2.000 EXP, a heal from the healing spell with 350 HP get me 30 EXP. I only use it if i need the heal, not for the levelup of this skill.
I choose the paladin, because i thought he has the only skill (avoid 50% damage at time) for Asmadeo, but in over 20 fights it don´t trigger once, it seems it don´t work mit Asmadeo. But i don´t really need it.
If there is no maxlevel of Asmadeo i should reach level 200 at the end of the game, or more.....if he makes more damage, he makes more EXP and he gets later on really much HP and Damage each level.
The only thing that i cheatet is that i give me with the editor a few items (e.g two 15% Damagereduction shoes, one because you can get it (if lucky) without cheating and the second because i cannot reach the medal for damagereduction because i don´t use spells) and a stack from 999 skeleton at the beginning of the game. But only to die, not to make damage or win the first rounds.
English is not my main language, if i wrote anything that is not understandably please ask