Cave keys are never irrelevant. Highest runes I've seen on someone so far is a level 12. Always having at least 1050 during the rebate event is recommended for the ultimate essence. Treasure sage is recommended only if you get the 30% at least but preferably the 40% discount. Otherwise at least 20% on the daily specials for advanced refines. Best event though is the TenTen treasure one though it requires ingots not coupons. Highest level maga I've seen so far is like an 8? You'll get their naturally over time so unless you have a lots to burn, you can put them into other things instead. Myoboku is pretty good for power still. Esp. since it affects all characters.

If you feel like you have high BP compared to others and lack ninjas, then go for event ninjas. They can beat someone with 10k-20k more BP if have right formation and high initiative. If you have ninja and lack BP and dont know to spend coupon then buy charm materials. After that buy all initiatives clothing.

If you have low BP and few ninjas, then i suggest getting at least two event ninjas ofcourse not neglecting initiatives. Power with 90k vs power with 80k has no difference. if the power 80k has higher initiative and better ninja than the 90k then 70% you win all the time.

I am level 91 with power of 84k and use kisame fusion and edo deidara, recently beat 100k power in SWB(which is rare) and i got around 7600 initiatives in Pos1. My Pos1 always attack first than his Pos1. Deidara scaling is scary, round 2 deidara mystery, I literally damages 60% hp of all his ninjas plus ignite them. By the end of round 2, 2 ninja die and the remaining at the death door.

The point here is that if you have better ninja and better initiative, if your not dumb, then 70% you win all the time.

If i remember right you are an over 150k power whale that owns edo hashirama, so what you actually need is to endure better the hits on move 2-4 to avoid being in battles where you are just a glass cannon.

Yes I am over 150k bp, But I do not have Edo Hashirama. I'm not really concerned about ninjas anymore, I'm really just looking for the most cost effective way to get stronger. Mt. myobuko is not really worth me spending into anymore because each upgrade is now 128/1. Adv refines just take a while to stack to the 500 for the rebate.

Is it better to prioritize getting charms or adv refines in events? 2 of my ninjas already have lv8 charms (The rest are lv 7) and all my ninjas have at a minimum of lv 8 with refines.

So at this point would I be better just buying cave key packs?

ICEx's stacking thread has some good info. Don't think lvl 9 charms worth it unless you have like lvl11- 12 stones.

Not sure lucky board is that good for high power since charms cost around 140 and adv refines cost 80(somewhat bearable). Sage key seems to be the best . Daily discount shop would be good too if they put 30%+ discounts ..balloon event would be good too if they put charms and cave keys and summon cultivation...recharge can be nice with like 1000 summon cultivation packs for 10k recharge etc.

If you have been keeping things even so far it might not be a bad idea to break down materials to stack up your position 1 ninja. Using my self as an example my bp is around 130k with my 3 star po 1 at 45k po 2 around 30k and the rest between 26-28k, so your position 1 should be around 52k if its stacked well. The 3k or so bp losses is made up by the shear out put of damage i do and how its less punishable due to my initiative stat.