It is supposed to be better than Mint
It used to be that Yu-Gi-Oh
Hasbro clearly understands the risks that counterfeiting poses to their business, and I wouldnt be shocked if they have plenty of connections in China that could help them out quite a bit
Those two have hit various ban lists, but the idea was to evoke a Grief on turn 1 (or a Fury later on), and follow up the sacrifice trigger with Undying Malice or a similar scam effect, doubling up that elementals ETB effect and keeping the body in play
You can play out vampires one by one and get an extra +1/+1 on board for each one you cast, or you could play token-makers like Charismatic Conqueror and Bloodline Keeper // Lord of Lineage to spread that vampire lord effect across more bodies with a single card from your hand
PSE Prismatic Secret Rare Hamon, Lord of Striking Thunder X LIGHT Level 10 [ ThunderEffect ] ATK 4000 DEF 4000 Cannot be Normal Summoned/Set