You won't see a lot of Death-elemental attacks, but as every one of them (predictably) causes KO, that's certainly not a bad thing. The ProRing, White Robe, and Ribbon all protect you against Death, so by the time you reach the end game you should be well-protected from these attacks. As you might expect, a lot of monsters resist Death, making the Death-based spells you get pretty bad. Strangely, there are no multi-target Death-elemental spells (though the ultra-rare IronGOLS have a multi-target Deathspecial attack).
You won't see a lot of Death-elemental attacks, but as every one of them (predictably) causes KO, that's certainly not a bad thing. The Protect Ring, White Robe, and Ribbon all protect you against Death, so by the time you reach the end game you should be well-protected from these attacks. As you might expect, a lot of monsters resist Death, making the Death-based spells you get pretty bad. Strangely, there are no multi-target Death-elemental spells (though the ultra-rare Iron Golems have a multi-target Deathspecial attack). Instead, all multi-target KOspells are of other elements. Weird!
Death is the element of the Deathspell, and that's it. You will rarely run into this spell, so Death resistance isn't a huge priority. Plenty of monsters, including all Undead, resist or are immune to Death. Stick with Matter-elemental KOspells for offensive use.