Magic tree for ktn??

Question so i bought magic tree before even looking up builds and put sp up to lvl 7 impact but do i even need impact my ktn is lvl 43 so should i just restart??

 

Impact is needed if u want to combo it with tenryu(startup)or make it easier to peform quick smited zantei' so I suggest u keep it

 

katanas have lower magic power than other weapons, but they can still use it for proration. there are some magical katanas to support those builds with additional magic
impact works very well with senbonzakura (forgot the skill name, it's the pretty one) since it's an AoE attack.

magic arrows is the strongest tier 0 skill, even without weapon bonus, because it has the power of a tier 1 skill but still costs just 1mp.
javelin is instant casted and inflicts elemental ailments.
lances is more suited for long range fighting, so you most likely don't need it and can leave it at lv5 to get impact.