I have a son named [name_m]Kaius[/name_m] & I’m pregnant with
Another boy…the only name i like is [name_m]Kian[/name_m]…does
[name_m]Kaius[/name_m] & [name_m]Kian[/name_m] sound too matchy?
Matchy? I don’t think so. [name_m]Kian[/name_m] is pronounced Kee-an and [name_m]Kaius[/name_m] is Kie-us so the only similarity is the K sound at the beginning. I think you have THE name 
You just have to think about if you were to have another boy would you feel the need to have a K name?
Good luck.
I think it’s fine. [name_u]Love[/name_u] the name [name_m]Kian[/name_m]!
Sorry, but I think they are much too close. I would keep looking and you could use [name_m]Kian[/name_m] in the middle spot.
[name_m]How[/name_m] are you pronouncing them? [name_u]KYE[/name_u]-us and KEE-an? I think that makes them well-matched without rhyming. Personally, I like for my kids’ names not to repeat initials, but then I have a lot of kids so that’s a practical matter. I wouldn’t choose to give my kids rhyming names, but names that share some sounds or letters without actually rhyming or being the same name with just one letter/sound different ([name_f]Holly[/name_f]/[name_f]Molly[/name_f]; Taylin/[name_m]Talen[/name_m]; [name_m]Mike[/name_m]/[name_m]Mick[/name_m]) can make for a nice set. I think the only challenge would come if you have more kids and feel locked into a pattern of unusual K names.