After a wholly lot of trial and error, I finally did it. I made Loki Prime invincible. May I present to you, the path to immortality (until an Eximus saps all your energy).
Flow gives a rank 30 Loki Prime 525 energy. The 525 energy is then used for Quick Thinking, which allows your health to never drop below 2 as long as you still have energy left. Rage returns some energy when you take damage, which feeds your energy pool, which then feeds Quick Thinking. And the Energy Siphon is there because, energy regeneration.
I've put in Streamline and Fleeting Expertise for the 75% energy efficiency - in case of emergency situations when I need to cast any of my abilities for cheap. Overextended is there for my Radial Disarm, but when I run solo, I throw on a Steel Fibre instead (it is a lot better). Vitality provides some much needed health for Rage to be effective.
Go on, have fun! Do note that I only run this build when I'm in the troll mood! I have a proper build which I run when I am with a team, so please feel at ease when I join you for endless defence! xP