100% IV Kingra | should I power it up?

I guess we would need to know a little more about what you would need it for (do you need attackers? defenders? prestigers?). Looking at its CP of 253 is a deterrent for me. You would need to spend a ton of dust to get it up to snuff. The next thing I look at is the moveset. If you had DB/Blizzard or DB/Outrage, you could at least use it as a Dragonite prestiger which would be cool. Finally, looking at its stats, it is not stellar. I think there are some more viable / easier to obtain options like Kingler who outclasses Kingdra in ATK and DEF, or Poliwrath who is more well-rounded overall. My personal opinion is no, do not power it up, but it is YOUR mon and if YOU like it for whatever reason go for it!

What are you going to use it as?

Just giving a quick look at your dust I would not power him up, save dust and resources until you can make him "usable" and then make the decision. Without knowing further about your character, your other offense and defense mon, your level, etc I would not say yes or no, but I would not invest on a mon like him without having already a decent team of attackers and defenders and a nice amount of dust.

Second glance wouldn't this Kingdra be a good defender?

Water typing covering Tyranitar, Rhydon.

Weak against dragons but got dragon breath so its pays back?

DB is Op, u can dodge easily and make alot of damage, HP is a good move and it has stab,nd 100% iv is just wow, yeah u should but up to you.

I also have a 100% IV DB/HP CP 2077. I want to power him up but for the reason all mentioned I havent. I feel your pain but don't waste the dust. LVL 31