Death: 歹
歹 (がつへん) is associated with death or what remains after death. 殉 means martyrdom, while 殖 means to increase and 殊 means especially; these meanings show that the component is only a clue, not a full definition.
殊 and 殉 have 10 strokes each; 殖 has 12. In each character, keep the left 歹 distinct from the right component.