SHIN SEKAI: SPARK OF THE NEW WORLD
the nature of Kojiro's ability was was quite simple. he had the ability to create highly impenetrable barriers in front of and around anything, but this great power had a huge flaw that many people knew. the barriers were so powerful that nothing except breathable air could pass through them, not even the transmission waves of magical energy, and it was worked from both inside and outside. so if Kojiro were to cover himself in the barrier, he would gain the ultimate protection but he would be unable to cover others, and if he covered others, he would be unable to cover himself. in this situation he chose the latter and put the safety of the school first.