Heroic,
My findan build:
Attack Tactics, Archery ,
WarMachines Balista, Imbue Balista , Triple Balista
Enlightment Inteligence
Destructive Master x3
Luck Soldier's Luck, Elven Luck,
I've kept restarting mission 1 till i got WarMachines on the WitchHut reachable on day one. Got all the stat boosts in all missions (now i'm on mission 4 academy campaign and Findan has obscene stats (40ATT 30DEF 23SP 33K) and 500+ mana). Of course he did not have those stats at the start of mission V of elven campaign but still.
Some actual tips:
Talanar starts with Nature's Luck, Battle Frenzy and Nature's Wrath.
Most of the starting troops (Sprites//Blade Dancers//Hunters) shoud go to him. In this mission Talanar wreaks havoc with low level units against walkers//flyers.
Findan should be able to clean the starting island with only a couple of 1 unit stack decoys thanks to his uber ballista and destructive.
Dirael has poor stats, and low mana pool - I used her mostly as a mule.
Week1:
Cash all the gold chests,flag all dwelings (hunter,pixies) and all mines (on starting island), build max gold income (capitol ) and if possible castles in both towns in week one.
Week2:
On week two finish clearing all monsters on starting island, upgrate pixies and hunters in one castle and send Findan past the garnison -> i only lost a pixie decoy to the garnison but it cost me almost all Findan' Mana (triple implosion ballista). Flag the abandoned mines and jump trough two way portal and go towards first necro town. Be sure to set skeleton archers as racial enemy before u leave.Oher undead types kinda optional, mabye also set spectral dragons aswell.
Week3-4:
On week tree Raven attacked me with superior forces. However i trashed a couple of her stacks and first chance she got she fleed.(since my findan has no resurection i will rely on forcing the enemy to flee as much as posible).
...
By the time i get to the poor defended necro town Talanar got me some ancient treants along with other reinforcements from back home. I only used treants on the castle assault and only lost one or two due to tower fire.
Then i slowly made my way towards the center underground necro town. The hardest battle of the whole mission for me happened here .
Good hero, godly initiative artifacts and a big stack of skeleton archers that always got to fire ahead of my master hunters and druids. Had to bring master hunters and druids to use Findans speciality and thus limit the devastating skeleton archers first strike. Had also to bring pixies to die instead of the hunters (lost about 300 of the this fight
).
But after this battle i got the initiative artifacts (two rings). I the cleared all the underground (all dwarven artifacts, bow of no range penalty all stats boosters) and emerged on Nicolai's island. (make shure u bring all your troops for this one mabybe except dancers to split hunters - big battle to follow).
Some Necro hero attacked me soon with a good army but ->
before combat starts hunters and druids take down a couple thowsands of skeletons (all of them) . And after that thanks to the initiative artifacts and general slowness of undead troops, dragons,balista, hunters, pixies, druids all get to before the enemy -> more stacks insta droped and Vladimir flees first chance he gets.
A couple more fights happened afterwards but the enemy had fewer troops and i got even more.
Visit all boosters ,finish all, spectral dragons,visit all 3 lvl up trees (findan gets lvl 34), finish off Nicolai, end campaign.
Because of no resurection u must strike fast and hard, bring as many troops to battle as possible to make the opponent flee before they get a chance to strike back. Only time it didn't work so well was the castle assault of a good hero with good troops and good(imba) artifacts and took some notable loses there (sprites). I always choosed Attack bosus on all arena visited trought the campaign because of this.
I am stuck on this campaign. I have read the walk thru's etc. but still no luck. Just cannot seem to master the correct way to win this. I would like to complete as this is the furthest I have come to finishing a complete heroes campaign. 
At this timeline I am guessing I will be out of luck to win again. 
