Here is the easiest and fastest routine on highest difficulty with auto-save and manul block (I have reach lv30 and became anti hero). You don't need to burn a single village or raid caravan
Start game regardless of your background. Go for wisdom and chrisma, at least have pathfinding of 2 and 2 at every med skill. Then pray to God you don't spawn in the khanate.
Travel to Zendar, drop all important once-only equipment in the box without talking to the blood fountain.
Now, if you started the game with horse, good. You keep a sword/crossbow/blood banner and go for looters (looters only) until you get the shovel
If you started without shovel or horse, sell anything except your main wepon and the staff you should already left at zendar and go to pick up raven and ork (pretty close to each other) If you manage to find Fientis around the north, recruit him and take his sword. Go to any nord village and recruit once. Make sure your party has less than 10, more than 5. DO NOT GO TO KHANATE OR OLD ZENDAR. Find looter and get the shovel.
Now disband your party, travel to any rhodok city and starts grave digging. (Rhodok troops suck at melee due to spear issue, if you have high start stat you can take four of them easily)
Dig until you become DEATH.
Now go for mortal companion set A. Check the companion guide online. (People in set A are generally good natured)
Go for Dupin, ork, and ash. Don't recruit raven and Thorn. Thorn could be a serial killer, Raven dislike Dupin and ork.
Now you can go punishing the necromancers for cheating death. You are death and therefore you shall rise wherever you have fallen. Their little dark art are mere joke to death, as death shall be the end of all, and there is no exception. However, there are still things you need to beware of, for you don't want to lose your gear by defeat.
Beware of the following troops:
HORROR with lance(very stupid but deadly, just one good coached hit can take you down)
Horror with hammer (still deal some damage to you)
Fleshburner with lance
Plague Doctor with hammer (same)
Blood Preserver with the projectile (blunt damage)
Shadow Lord with the mace (beware, extremely deadly with the speed of their horse)
Any kind of golem(DO NOT RUSH INTO THEM use your full reach to deal with them)
Shadow Knight (easy kill, don't give them the chance to swing, don't stand in front of their coached helberd.Also remember the shadow sword has potential to deal great damage to you when thurst)
Destroyer (Same as golems)
ANY BLOOD ENGINE TYPE MONSTER(I call them DEATH BANE. You don't want to be hit by them.)
Werewolf and vampire(just...stay away from werewolf until you get more than double numbered troops)
Surprisingly you will find grind exp from necromancers is not a good idea as their troops are rarely high leveled.
You can take nearly all kinds of necromancer party by yourself EXCEPT ARTIFICER. Don't mass with artificers unless you have at least half their number of highest tier troops.
During your level up process, I strongly suggest you get your wisdom and chrisma to 18. Leadership, all medi skill, training and pathfinding to 6. Pathfinding and leadership should be the priority. Pathfinding is essential for servival and leadership give you more troops to spend.
In regard of troop choice, I recommand slayers before lv30. They often get destroyed near old zendar by necromancers. By hunting necromancers you could quickly get a large group of them. They are generally your best chance for fighting necromancers at this stage.
Before get 4 riding, plague doctor's horse is your best choice. After you get 4, hell raiser's horse. All the way until you get to lv30.
Kill necromancer party is the quickest way to earn money as horror almost always drop large amount of undamaged two handed sword which has good selling price.
In all necromancer gears, shadow sword, shadow helberd, destroyer's harmmer, blood engine canon, horse of plague doctor, hell raiser and shadow lord are some of the best drops. They are generally the staff you want to get.
When you get your wisdom and chrisma to 18, start to work your A to 12 and S to 21. (or reverse if you want to become vampire)
Once you get the necromancer gears I mentioned above, stop grind necromancers. Become mercenary and start to siege castles. Human troops generally have higher exp and cause few damage to you. Still, a thrown axe, bolt or arrow from a huscarl or sharpshooter in your face can deal great damage. Other than that you are pretty much invincible. Every city and castle is exp pack for you. Grind all your way to lv30 is piece of cake now.
Regretablly, you cannot get horseman's curse as it is just too risky to die, but relic master force you to have a deal with bloodfountain anyway. So be a badass and don't bent knees to Bloodfountain for power. (Through this build I still supply you with necessary stat to become werewolf/Vampire and lich.)
Oh, if you are possessed and get killed in my early steps, feel sorry for you
Go grind mortal army for 60000 as soon as possible with your own strong army and talk to the reader for exocism as soon as possible. If you play on good AI, almost every archer go for your head with laser accuracy all the time, your 50 protection horror mask will not protect you from even 1 head shot from high tier mortal/necromancer units.
Sorry for the spelling and grammer mistakes. I must have made tons of them.