TMI, with the tag 'halo', the shape and color of the halos were a little to 'diverse'. Turns out Blue Archive introduced some various shapes of halo, so I put blue archive in the negative point but this time the overall image was seriouslt degraded. Turns out 'traditional halo' was the correct tag I was looking for, with an addition of 'faded halo' to illustrate the angel dying.