Dark Giant is the fourth and last dark power received in Jak II. Dark Jak obtains this power after bringing 100 skull gems to the oracle at its hut. For an unknown reason, Jak loses this ability by Jak 3.
This power allows Dark Jak to grow three times his usual size, deal extreme damage, and allows him to jump much higher than normal. To gain this form, press 
while in Dark mode (or twice).
Dark Giant can survive a robot guard blaster shot. If you only get hit once, he will be left with only 1 health point. If you morph into Dark Giant inside Haven City, the Krimzon Guard will go into a major situation.