Good idea yujy , since dmg gain is in %, hp should be done same way. And there ownt be 12k sprites with 46hp
For changing go to sessions/re sands/exp_system/exp_system_cfg.txt file and try to make same to hp strings, as it`s for dmg.
damage_bonus=2 // in percents -- äë˙ âńĺăî äŕěŕćŕůĺăî
special_bonus=2 // in percents -- äë˙ ďđčçűâíűő ŕáčëîę
health_bonus=5 // abs -- őĺëöű
Dmg and special skill have bonus in %, while hp get absolute(abs) amount 5hp/lvl. Replace `abs` with `in percents` for health_bonus , and this should do it.