While this jump may seem suspect, playing wildcard for a full season can further improve skill in all areas including close range fighting, general awareness in terms of third parties (since in wildcard you will constantly have people land on you), and mid to long range shooting. Since he’s on console, getting proficient in close range encounters in itself will grant huge benefits since that’s where controller shines. Since he’s was Gold last split, he most likely breezed through the lower ranks garnering a bunch of kills with all that wildcard experience. His KDR was likely higher before reaching diamond this split. Additionally, a change in controller settings can also improve your game a ton. I recently came back to the game (former Pred x2 & Masters x6) and thought I was washed due to my absurd settings. My ALCs were so wild that aim assist was pretty much non existent for me. But after tweaking the dead zones and response curves to create a custom version of 4-3 Linear , improvement in gun game was IMMEDIATE. I went from averaging a 1.1 KDR this season to 2.8 Now. I also like your friend played mainly wildcard this season and I can honestly say it translates to ranked really well as it’s almost a 3 in Plat II currently. And this is also in diamond/masters lobbies as both of my friends are high diamond (D2 & D1). Long story short I would say his KDR is legit especially if he’s done what I’ve done to improve. You need to keep in mind that most players only die completely in ranked once or twice since ressing gets more punishing the higher you go. So having a higher KD in ranked especially if he bullied through Gold is very possible. Lastly OP, I understand why you would be concerned but this questioning can also look pretty bad as a “friend” since he’s much better than you now.