sad, pitiful, wretched, cruel
慘 centers on deep emotional pain: sadness, pitifulness, and wretchedness. The cruel sense extends this to causing such pain in others.
慘 combines 忄 (heart/mind) with 參, which likely contributes the sound and may relate to gathering or accumulation, suggesting accumulated emotional pain.
The heart radical 忄 beside 參, which looks like a gathering of many strands, suggests a heart weighed down by accumulated sorrows—pitiful and wretched.
For サン, imagine a sad scene under the sun: the sun (サン) shines down on a pitiful, wretched figure, making the sadness feel even more cruel.