Many people may not be happy with this topic but it almost got another topic locked so I thought it would be best to start a new one.
Reasons for Loken being a psyker
Extreme stress after Istvaan caused him to almost lose his mind, more than enough to awake latent powers,
Possible founder of the GK, the 8 marines brought before the Emp were all said to possess the needed "powers", or something like that,
Dan Abnett created Loken so really he can do what he wants with him, meaning that if