The song's buildup is wonderful and sounds inspirational, as if gaining a second wind or the courage to stand up for a friend who's been hurt badly by some isekai villain.
The main tune sounds alright. The drums at 1:06 seem a little out of place to me. If it had been a harder hitting drum piece with heavy reverb, probably would have sounded pretty nice there. Around 2:00, the sudden build back into the beat is rather sudden but not something that really puts one off from the beat too much.
The sudden overall change in tempo at 3:49 is also entirely strange and doesn't fit very well, if anything it clashes with the beat as it comes out of nowhere and the rest of the song never does anything like that again.
Overall, the tune is decent but there are definitely parts that could have been changed up or improved. Outside of the few spots I noted, I think this was a rather decent melody in and of itself.