Kindred and Tahm Kench (concerning the lore)

Hello everyone !

I know that there's not a lot of people that actually pay attention to the game's lore (or is there ?), but I'm one of those, and I am quite intrigued with Kindred and Tahm Kench's involvement in the League of Legends. I mean, those two basically exist since the beginning of time - as Tahm Kench is a Crossroad demon, and Kindred is/are litteraly Death (or a least a Reaper) - and yet, both joined the League of Legends. "Why ?" is my question. Why would Death allow mortal beings (Summoners) to control/summon her, and why would a Crossroad demon even want that ? Tahm Kench is a selfish being who only wants to eat and takes pleasure from his victims' sorrow, and Kindred... well she/they is/are the embodiment of death, so we don't really know what she/they want(s).

I tried to find an explanation, but I couldn't. Aatrox was a bit like them at first, but it was explainable in the end ; he's a warrior, takes pride from victory and all, so it is not really incoherent that he joined the League. But Kindred and Tahm Kench ? I'm clueless. They couldn't have just been invited to join the League and told themselves "Oh hey, why not ? Looks fun !".

So if any of you is a bit more imaginative than me, or at least as interested in the lore as me, please do share oyur thoughts on the matter ! (Am I the only one who actually wondered why those two fellas joined the League ? xD)