Original Post — Direct link

Credit to /u/IndianaCrash for tipping me off, view his thing here:

https://www.reddit.com/r/leagueoflegends/comments/dp67za/nobody_is_talking_about_the_thresh_vs_senna_event/

When Senna gains 100 Souls - Thresh's number appears to be irrelevant, as I gained 100+ Souls and the event never procced, plus Senna's 100 Souls is a pain to get - a sidequest appears.

This is Senna's description:

https://images-ext-1.discordapp.net/external/LkX4STFGLX4oaNqPPWJf9QhmO5iXR-N3y9N_lw96c7g/https/puu.sh/EyOAb/161c4a95e3.jpg?width=863&height=676

This is Thresh's:

https://i.imgur.com/m5icLAW.jpg

Upon killing Thresh as Senna (or presumably Lucian), Senna gains 40 AP and Armour:

https://i.imgur.com/SMkjD4V.jpg

When Thresh kills Senna, he gains 50 Range, 40 AD, and 30 Crit Chance.

https://i.imgur.com/AtWfLIe.jpg

Presumably he gains the same bonuses with a different description if he kills Lucian.

Thresh does not appear to lose his Souls when Senna is victorious, according to my friend who I tested with. I'd love to test this more thoroughly and see Lucian's interactions but it's a bit of a drag to get to.

External link →
about 5 years ago - /u/RiotAugust - Direct link

Senna and Lucian get 30 AP and Armor (equivalent to 40 Thresh souls)

If Senna and Lucian are on the same team they will each get a separate quest to kill Thresh. If Thresh manages to kill both of them he will get 2x the mist stacks.

about 5 years ago - /u/RiotAugust - Direct link

Originally posted by intothepride

rengar/kha event is out of the competitive games, I would assume that senna-thresh will be taken out too, however, it will be in soloQ ranked obviously

Rengar/Kha are in comp games.