You can use his ability to add rats to your hard from your deck
Firstly, its probably important to mention that many MTG players who have read this card are pretty sure that its incredibly powerful
This "Merc Triptych" featuring Jackie Welles, V (Corporate Exile), and Viktor Vektor looks phenomenal
While Darkwurm's Pendulum Effect is a 1 card full Scales, as it activates a "Supreme King Gate" from Deck into your other Scale, it does have quite a restriction in that you can only Pendulum Summon DARK Monsters for the rest of the turn
Not to mention the potential synergies you can have with cards that do something good when they are turned face up
When to buy 2-4 weeks after release January-March, August-September At or below retail price, never above When NOT to buy During pre-orders / release week During the holiday season After a viral buzz / FOMO When prices are +30% above retail When to sell The "when to sell" question depends on your goals