Guide for 3rd level boss?

[Ａｎｏｎｅｍｅｓｉｓ]

I can only get to the final troll boss with 1 unit what is the strategy?

[Bonzai101]

For the ice troll boss :
1st phase, leave the crystal that is inline with the boss, destroy the others each round.
2nd phase, destroy the green crystals for large damage on the boss, or engage the boss directly.

I'm unsure why you mentioned 3rd boss here........

[Linguistically Inept]

with only one unit? you're pretty much screwed, you almost need a certain amount of actions per round (not counting aoe; but thats unreliable)

at the end of each round the cultists will explode one of the remaining red crystals dealing damage a couple of hexes to the left or right; this is how you damage the boss

a red crystal will always spawn that will hit the boss; so the gameplan is to destroy every other crystal except that one (so its the one the cultists explode and hits the boss)... if theres multiple crystals at the end of a round then the cultists will randomly choose but also the ones that arent chosen shoot a laser at one of your units (theres a range limit so potentially theyll do nothing, but its not something you should count on)

after a few of these crystal hits (4? icr) the boss goes into next phase where he will move around and actually attack... the crystals he spawns in this phase are green; they wont explode or shoot lasers but they will heal him at the end of the round if they arent destroyed

destroying a green crystal deals 3 damage and if left then they heal him for 3 health effectively this means if your attack deals more than 6 damage then you're better off just hitting the boss (and its quite easy -atleast with a full party- to just focus him down in one round rather than destroying crystals; which if you can do means any attack over 3 damage -so basically anything- is better aimed at the boss)