not really disagreeing but how does 
fit the themantics?
Darkness has things that are considered bad to modern ethics, like Steal, and also has things like Parasite and Devourer. I think it fits it well.
I think +3 | +3 is too much. Life has mitosis, it can easily spam food for the troll.
Also, the troll is regenerating: after a single cannibalize, a 7|7 regenerating troll is nearly impossible to kill with a single card (except Fire Bolt and similar). It needs 2 poison counters only to stop regenerating, not even damaging him!!!
I think +2 | +2 is more fitting (like growth), and i think the regeneration should be limited to 1.
Yes, life has Mitosis, but even if Mitosis creature is a photon, its still an expensive combo that uses 3 cards. This for a 3/3 gain that uses 2 quanta types. Upped Steam Machine has already 15 HP, and gain +4 attack per turn, just using quanta and without other cards. And Water has much more stall arsenal.
Difficult to kill, yeah, nearly impossible, no. Regenerating is a good option vs Fire Shield, or Plague, but you can play Gravity Pull, AM, Rewind, Basilisk Blood, Congeal... Ok, most options here dont kill, but make it useless
My opinion: regeneration is ok. About 3/3 being to much, I can agree. I wouldnt like it being 2/2 exactly because of growth. 1/1 = devour; 2/2 = growth; 2/0 = ablaze. How about 3/1 to cannibalize? This would even add Maxwell Demon as effective control for unupped troll. I can think about reducing the initial attack as wel, but reducing the attack gain of cannibalize to less tha 3 would make it useless most times (better just let the creature instead of cannibalize it).
More opinions?
