Edison format ruling
Shadow Delver
Card effect (current official text)This card is treated as a Normal Monster while face-up on the field or in the Graveyard. While this card is face-up on the field, you can Normal Summon it to have it be treated as an Effect Monster with this effect:
● Once per turn, you can select 1 face-up Level 4 or lower DARK monster you control. It can attack your opponent directly this turn.
Rulings
- If a monster makes a direct attack using the effect Shadow Delver, and ceases to be a Level 4 or lower DARK monster after the attack is declared, the attack still continues. No replay occurs.
Rulings data courtesy of Format Library — formatlibrary.com. Spotted an inaccuracy? Flag it in the Edison forum — sourced change requests get reviewed.