depends on the other 3 ninjas

Does not matter. In late-game you gotta have all the mains anyways and can adjust accordingly.

Depends on the ninja you have unlocked and how your sage bracket is like, also we will get main skill upgrades sometime which makes things a bit the reason why water is 2nd.... Space-time is just adapt as needed :

1. Earth (Still the best for late game, look at the top in CN and it's still Earth pretty much.... He gets super annoying with skill upgrades but mostly it's just cuz the metas all work well)

2. Water (pos1 shark bomb + 5 kage madara = cancer af..... and if ever thrown in Kakashi Susanoo -_- new main skills shark bomb adds paralyze) Also with new main skills healing tips gets even better, if they got edo hashi + naruto 6 path/ kurama link + Tsunade Hokage (or even Sakura Summer but not really as great) it's hell too.

3.Wind (mainly for refresh on skills of other ninja and clone spam, depends on who you use.... an AGK team or maybe Temari swimsuit when her Y skills come is strong)

4.Fire (full support, it's hard to place exactly since it's very situational.... skill upgrades come he can be 2nd or 3rd depending on what you do then)

5.Lightning (Straight blitz to end ASAP and not much to do without root, that can be removed pretty easily now)

Skill upgrade list: https://docs.google.com/do*ent/d/1NugtF12K5S1lPNH1vkE2cp5mjV9kEvJDLdaWFY_V610/edit .... Mains are at the end, all credit to Oppai Paizuri

anyone know the price of christmas armor in lucky board

I don't know who is the best main, but lightning main is definitely the worst. He is pretty much unplayable in current meta.

around 6k.