odn = Odin (Agrippa ending)
tyr = Tyr (Alexander Ending)
lke = Loki [sometimes spelled Loke] (Revenge Ending)

They're all very prominent figures in Norse mythology.

Odin is the "all father" of Asgard, and is associated with things like wisdom, death and war. This sounds the most like Weyer to me, and in the ending that nets you this code, Daniel "dies" and the assumingly omniscient Weyer and Agrippa seem to be pulling some strings. Also, Odin sacrificed one of his eyes and hung upside down from a holy tree to drink from the Well of Wisdom, which reminds me of Agrippa's own sacrifice to enter the orb's portal with his pupil.

Tyr is the god of war. His origins are shady. Nobody really knows how old he is, and he's rumored to be a lot older than the rest of the gods of Asgard. He sacrificed his hand/arm in a successful attempt to bind/tame the wolf-beast Fenrir. This code is gotten with the ending in which Alexander succeeds, and I think some of the parallels are obvious. Alexander has mysteriously outlived the rest of the nobles by centuries, and has devoted his entire life to relentless pursuit of the power of the orb. If anyone, he's our war-god.

Loki isn't a god at all, but is an immensely powerful shapeshifter with a penchant for mischief. He sows the seeds of discord, but is typically under the favor of Odin (sometimes believed to be his brother). This is shakiest link by far, but the idea of Alexander falling to even his best laid plans by a man far less powerful and supposedly under his control is very Loki indeed. Daniel's subterfuge is far less intense than Loki's ever was, but he did drink the amnesia drought under Alexander's nose to prepare himself to kill him when Alexander least expected it to be coming from a "trusted ally".

So there you have it. Weyer/Agrippa as Odin, Alexander and Tyr, and Daniel as Loki. I only hope that I'm not reading far too much into something that wasn't intended, but I still think it's pretty interesting.