The Ancient one help.

Hey all, i've hit a wall in the campiagn. i cant beat the ancient one for the life of me. ive got spire with a BS and a GC with 2 SM fleets as backups. all strike cruisers mk 2. is there something about this fight im missing? even with the best ships in the game i cant kill the smaller ones fast enough. any tips would be appreciated.

A battleship is actually pretty bad agains the Ancient One, as the Tyranids are too quick and board Spire to death. Gamey variant: Bring Spire in a light cruiser and warp him out as quickly as possible, and spam Nova Cannons backed up with boarding focused Space Marines, and board the AO to death. Because reducing it to 0 crew kills it. They patched this a bit so it is more difficult now. The other not that gamey variant is to bring Spire and his fleet, Spire in an Apocalypse-class BS, snipe with him while trying to kite away (thanks to the lock on range boost for Apocs this can work in combination with MWJ), and a shitload of cruisers. Strength in numbers. Backed up AGAIN by Space Marines. I did it in my first go this way.

My suggestion is to 'cheese' it. Put Spire in the smallest ship you can as his flagship and tuck him away in a gas cloud near your deployment zone.
Next, take all strike cruiser mk2s and a couple of hunters. Have 2 fleets of SMs for this purpose.

The intention is to board the ancient one until it dies. Nothing else matters, don't fire or attack the other ships, they infinite respawn. The Mk2 is my choice because they have boarding torpedoes. On the level I played this I had Spire on a cruiser, 5 strike cruiser mk2s and 2 hunters.

Rush the ancient one and unleash every boarding trick you have. Honour the chapter, boarding, boarding torpedoes, assault boats.

You need to kill ~160 crew on the Ancient One so just stack on boarding stack after boarding stack. Do not worry about anything else. You will suffer heavy losses, but you will win. I had more strike cruisers come in a second wave and they did the coup de grace with boarding torpedoes.

By this stage such losses are easily made up by the resources you have, and it's worth it not to have any more 'Nids invading you. Screenshot below of my results.

I did it with a combo of Retribution and Armageddon/Overlord class ships. Cycle launching melta torps to chip it down and then straight up ganging up on it when it closes in won the battle fairly quickly for me. Make sure Spire is not the first one in and he should avoid most boarding attempts.

Alternatively a full fleet of SM ships with lock on and bombardment cannons. Kite away, and as soon as the shields are down bombers and boarding should chip it down pretty comfortably without putting yourself in much danger.
And since bombardment cannons have longer range and if you kite well, setting the Ancient as prio 1 will ensure that most of your broadside firepower is directed towards the smaller ships.

found with nercrons with the proper flagship buffs i literally just rushed it with 3 big ships and charged at it b4 you could get over ran with tyranids because trying to kite that sucker is no good