Kindred is the Ruined King
Note: There are spoilers to the new Shadow and Fortune lores for Hecarim, Thresh, Kalista, Mordekaiser, and Karthus. If you have not read these, read them and come back. Thanks!
With the new Shadow Isle lore rewrite, a lot of new information has been uncovered relating to the origins of the Shadow Isles, as well as backstories for five Shadow Isle champions. I believe that Kindred is the "Ruined King" that we hear about in the lore. In Hecarim's new lore, it tells the story of a mad king and his ill wife, and the spell he cast in the Blessed Isles that transformed it into the Shadow Isles we know and love. All of the new lores connect to the spell and the consequences it brought, but people forget to remember why the king cast the spell in the first place. The king cast a spell to kill both himself and his wife and forever connect the two in death. I believe that Kindred's Wolf is the spirit of the Ruined King, and Lamb is the spirit of the deceased Queen. This would also connect because of Kindred's rivals: Karthis, Hecarim, Thresh, Yorick, and Mordekaiser. It is worth pointing out that in the second part of Kindred's lore, it is evident that Wolf and Lamb dearly care for each other, and may have been lovers in another time, but that's not confirmed evidence.
Edit: I would like to start off by saying that there is no detail connecting the events of the Shadow Isle lore to a certain time period. The only thing that is clear is that the Harrowing has been taking place for centuries. Secondly, I have been told that the event of the transformation from Blessed Isles the Shadow Isles was called the Ruination_
and compare it with the quotes of Lord and Lady Altars.