What I like most about Thornmantle is its an Elf that can kill Planeswalkers on an enter the battlefield trigger
Overall it is lower impact than Hearse, but costs less
Koll, the Forgemaster or other effects can change that, but thats the basic idea
Arcane Bombardment Arcane Heist Arcane Proxy Arcane Savant Bloodthirsty Adversary Blue Mage's Cane Chandra, Hope's Beacon Chandra, Pyromaster Demilich Dual Strike Elemental Expressionist Elite Arcanist Emeritus of Truce Ether Eye of the Storm Finale of Promise Flawless Forgery Founding the Third Path Galvanic Iteration God-Eternal Kefnet Impulsivity Increasing Vengeance Isochron Scepter Jaya, Fiery Negotiator Magar of the Magic Strings Mizzix's Mastery Mnemonic Deluge Muddle, the Ever-Changing Myra the Magnificent Mysterious Stranger Panoptic Mirror Psionic Ritual Refuse // Cooperate Renegade Bull Roving Actuator Saruman of Many Colors Signature Spells Skycoach Conductor Soundwave, Sonic Spy Spellbinder Spellbinding Soprano Spelltwine Spellweaver Volute Stella Lee, Wild Card Storm of Memories Stormsplitter Surge to Victory The Tale of Tamiyo Wizard's Spellbook Wizards of Thay
In other words, just by looking at it, it's literally a meaningless card