Troubles Of A New Age - Act 5 Story Quest
Troubles of A New Age is the first quest available to you in Act 5 of Titan Quest: Ragnarok. If you own the Ragnarok expansion pack after you defeat Hades and complete The Immortal Throne quest a Portal will open up, similar to what happened after you defeated Typhon in Act 3. Go through the Portal and you'll find yourself in the City of Corinth, the first town of Act 5.
After leaving the building you start in you'll automatically receive the Festivities Side Quest. You must complete this Side Quest in order to advance the main story forward; to complete it all you need to do is speak with 3 people in Corinth, one of those NPCs is Ariston who you'll need to speak to in order to begin the Troubles of A New Age quest.
Once you've completed Festivities and are ready to continue with the main quest head to the northern portion of Corinth where you'll find Stamatios, a guard, standing next to two other guards that are blocking your path. Speak with Stamatios and assuming that you've completed Festivities he will allow you to pass.
Follow the linear route to the Corinth Harbor Quarter where you will find Haimon the Dockmaster waving his arms to get your attention. Speak with him and then continue east to Lechaion Harbor behind him where you'll be fighting the first boss of Act 5.
Porcus the Ketos is the first boss of Act 5 and he will have 3 different phases. For the first phase you'll find Porcus on the western side of the harbor's shore, as shown in the screenshot above. Once you decrease his health to 2/3rds he will submerge and come up in an area a little bit east of here, out of melee range. During the second phase Porcus will summon a couple sets of monsters while spitting Poison at you and hitting you with ranged attacks.
Defeat all of the adds that Porcus summons and he will submerge again and come up near the Primitive Hoard sea shell chest (not too far from where he was in phase 2). Phase 3 works the same as the first phase, just whack him repeatedly until eventually you win. Dodge the Poison cloud he creates on the ground as even with max Poison Resistance it'll still hurt.
Phase 1: Porcus will be in melee range on the western side of the harbor's coast line. You can attack him until he submerges at 2/3rds health.
Phase 2: At 2/3rds health Porcus will submerge and move out of melee range. He will also summon 3 groups of Triton enemies which you must defeat to advance the fight to Phase 3.
Phase 3: Just like Phase 1 except Porcus is in a different location this time.
Recommended Resistances: Poison and Cold
Porcus the Ketos Attacks:
Bite: His standard melee attack
Poison Spit: His standard ranged attack
Poison Blob: Porcus will spit a blob of Poison at you that creates a puddle on the ground which deals heavy Poison damage over 6 seconds.
Tidal Wave: A wave of water will be sent at the target dealing Cold damage as well as stunning anyone it hits.
Once Porcus has been defeated return to Ariston in Corinth and speak with him to complete this quest. The next quest story quest begins by speaking with Ylva ~ Princess of Scandia a little bit to the south of Ariston; that quest is titled The Warrior Princess.