That's way too much info. Pretty much, he obsesses over the nature of the Darkness and the Hive, especially their gods and the Deathsong. He joined Eris's fireteam, but went missing after searching for the Deathsinger

His last price of research was on the killing word (song). It could kill a guardian but they could still come back from it. Toland wished to know if you could refine it to a point where a being is reduced to oblivion. Another point in his research is how can say the word(s) without they themselves perishing. He speculates that the singer becomes apart of the actual song or death itself.