Bored. May as well make an attempt to formulate this thing.
Name: Verasune
Description: None of my business.
Effect:
Adds 15 Attack and 15 Speed passively. User can choose to drain 5 chakra per turn to boost stats to 20 Attack and 20 Speed. This sword gains 1 counter every time it is used as the last hit in a won fight. Each counter on the sword passively boosts the users attack by 5. There can be a maximum of 5 stacks. However, upon losing a fight, two counters are lost. Each stack only lasts for 9 days (to ensure that you continue killing to keep its power).
Therefore: A maximum of 45 Attack and 20 Speed.
Thoughts, comments, religious beliefs? Does this need to be nerfed?