Location of The ArcanumFrom your spaceship, travel to the northeastern part of a map, Seat of Empire. There is The Arcanum Outpost, you are supposed to travel to.
Stop the Dread Guard Raid on ArcanumUpon entering Specimen Storage Complex of The Arcanum, you will be faced with couple of enemy ambushes, until you reach the end of the first platform.
Follow Lord TagrissFollowing Lord Tagriss will put you in the situations where you should make tricky jumps over a gaps between platforms. Be sure to check them out first, because some of them are hidden and it is hard to spot them between some platforms. You will come across a couple of enemy ambushes here as well, Unknown Creature Tentacles, and a lot of jumping.
Defeat Muur’s Patient ZeroPatient Zero does huge damage, and also has Perpetual Cell Division buff that heals him over a period of time. Lucky for you, he does not have a lot of health, and he can be down quickly if you organize well. Save you resources for interrupting one of his two spells, when he jumps back and summons four Propegated Rakling, bring them down fast, since their combine damage attacks might be lethal.
Note: Because of a gap between container with Patient Zero and a platform you are jumping from, it may happen that your companion will stay behind, on a platform, and not be able to help you during the fight. Resummon him/her before facing Patient Zero.