This was the first few turns of my legendary / very hard playthrough.
Turn 1 merge handmaiden and immediately kill the town to your west. Sack and then immediately occupy (always do this if you have movement to spare, literally no downside, free gold). Hire your 3 units (primarily archers)
Battle tactics are to use Alarielle and handmaiden in front, followed by tree dudes. People in general underestimate just how much lords can tank, even the non-fighty ones (note: against the AI, don’t try this vs humans - even when the AI has good killers/duelists they often use them poorly). Horsies do their flanking thing. Continually drop heals. Also take the time at the end of the battle to keep dropping heals.
Turn 2 move east. Your units should be healed to full health if you did the turn 1 fight optimally. Hire your 3.
Turn 3 kill east town. Hire your 3. Elfqueen should be level 3 with at least 1 level up invested into earth blood.
Turn 4-6 move west to gate. I ended up with 17 units (4 spears [2 hired], 7 archers [7 hired], 1 sisters, 1 dryad, 1 treekin, 1 elfqueen, 1 handmaiden, 1 horsie) so it looks like I force marched the entire way.
Turn 7 kill the gate. Pick one side of the map (left is better I think). Abuse the fuck out of tower and archer line of sight - the AI does not compensate for the fixed firing angle of their archers on the wall. Alarielle and the handmaiden up the walls first to tank, followed by spears and dryads. Don’t bother with the gate. Unfortunately the tree kin and horsies are useless here (even if they kill the gate there’s black guard which do and will murder them due to anti large anti armor). Remember you’re abusing line of fire so your archers should have free reign to fire on the wall without any retaliation. Keep dropping overcasted heals, etc etc.
Recorded the replay of that battle so you get an idea of how to abuse the AI. I ran my sisters up the wall so they could fire into the backside of the wall fight and into the troops the AI stupidly keeps on the ground not contributing, unfortunately they did get caught in the melee for a long time. If that didn’t happen this would’ve been over much sooner.
Turn 8-11 Heal then move down towards the big city. The AI had its stack in Chrace, so I was able to take a lolchokepoint battle at the bridge as he tried to move back. Normal field battle is also winnable. Point is to not let it garrison (though even then you could still win by again, abusing the crap out of the siege battle AI). Captured the city on turn 11, rest was mop up. Then it’s on to do whatever you want.
Also during all of this be making trade deals and NAPs and crap. No alliances, wait for the initial batch of elf fratricide to be declared (you don’t want to be pulled into anything).