It's because removing a monster with 20 fields from an SoA structure means resizing 20 arrays. Removing the same monster from an AoS array involves resizing a single array, which you're going to process in a very cache friendly way.

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Altern4tiveAcc 27 minutes ago | parent [-]

Assuming ordering isn't a concern, can't you just have a field called "removed" and skip those when iterating?

Or swap it with the last monster, and keeping an index for the last monster alive.

	▲	marcosdumay 7 minutes ago \| parent [-]
		Then you have to read the "removed" field on every field read on every operation. SoA is only useful when you don't read multiple fields for most operations.