为
wéi · HSK 2
by
为 (wéi) sounds like 'way' — done by way of someone
为 marks the agent in passive or formal constructions, often paired with 所: 被X为所Y means 'done by X'. The 'way' sound-hook links wéi to 'by way of', matching the 'by/for the sake of' meaning.
为 — simplified form of 為; from 爪 (claw/hand) over 象 (elephant)
The traditional form 為 originally depicted a hand leading an elephant, suggesting the act of doing or making work. Over time it generalized to mean 'to do, to act, for the sake of.' The simplified 为 preserves this 'do/for' meaning, with pronunciation shifting between wéi ('to be, to do') and wèi ('for, because of').