This is it, the final chapter! Start off by going forward until you meet up with Alecto. Slowly walk forward and when a barrier goes up, use the Eyes of Truth to dispel it. Another cutscene will occur and Kratos will end up on a boat. Here, you will have to fight some Spartan soldiers, with Tisiphone joining shortly with her bird. She has all of the same attacks as in the previous battle, although the arena is much smaller.
Keep attacking her until another cutscene occurs, which will eventually lead to the second phase of the battle. You'll be on the ship, still, but it's now up in the air, with Alecto's tentacle on the deck. Attack it and you'll see a barrier cover it, so use the Eyes of Truth to dispel it. One of the tentacles in the background will spit the black goo at you, so use the Oath Stone to escape it.
Once a white halo appears, grapple it to slice it and then you'll have to battle it again. This time, however, the tentacles in the back will start attacking you. There are three different attacks, with one of them being the goo attack from before, which damages you now. They also stab the ground in front of the one you need to hit, with the third stab being followed by it dragging across the ground. The last attack is two ground pounds.
Other than that, do the same as above, which is quickly followed by a cutscene with QTEs. Once you jump over a tentacle, keep an eye out for three grapple points and when prompted, hold L2 + R2 until your blade glows, then let go. In the water, there will be more QTEs and when you're on top of the sea monster's head, keep pressing Square to attack it until you eventually end up landing on a platform.
You'll now be face to face with the sea monster. Alecto has a few moves here to watch out for, but they're all telegraphed and easy to dodge. When all four tips glow, go to the back of the platform and double jump over the shockwave. She'll spit water at you, so go to the back, as she'll try to bite you. When two tips glow, go to the same side as those tentacles to avoid a stabbing attack. Note the spear on the ground, so pick it up and use it to help damage the beast when she's far away.
Eventually, Tisiphone will join the battle and she'll be alone for a short while. Try to do as much damage as possible to her before Alecto comes back. If she does come back, concentrate on Tisiphone until she goes away, then the battle will resume with Alecto, with it being the exact same as before. When you see the red halo, grapple Alecto and get ready for the final batch of QTEs, with a L2 + R2 hold like before. More QTEs follow and when you eventually see the red halo above Alecto's human form, grapple her to finish it for good.
Congratulations! You beat God of War: Ascension! Sit back and enjoy the ending!
