Tengu format ruling
The Legendary Fisherman

Card effect (current official text)While "Umi" is on the field, this card is unaffected by Spell effects and cannot be targeted for attacks, but does not prevent your opponent from attacking you directly.
Rulings
- If you Special Summon The Legendary Fisherman with Premature Burial, when Premature Burial is destroyed while Umi is face-up on the field The Legendary Fisherman is not destroyed.
- If a face-up The Legendary Fisherman is the only monster you control, when your opponent's monsters attack they attack you directly.
- If a Spell Card is activated that would destroy Umi and a face-up The Legendary Fisherman simultaneously, Umi is destroyed but The Legendary Fisherman is not.
- If your opponent has Messenger of Peace or Swords of Revealing Light face-up on their side of the field, The Legendary Fisherman can attack if Umi is face-up on the field. If your opponent has Toll, you do not pay. If your opponent has Gravekeeper's Servant, you do not send a card from the top of your Deck to your GY.
- If The Legendary Fisherman is equipped with Ring of Magnetism while Umi is face-up on the field, the effect of Ring of Magnetism is not applied.
- If your opponent controls a monster equipped with Ring of Magnetism and another monster, you can attack the other monster with The Legendary Fisherman if Umi is face-up on the field.
- If your opponent has The Dark Door face-up on their side of the field, you can attack with one of your monsters and then attack with The Legendary Fisherman if Umi is face-up on the field.
Rulings data courtesy of Format Library — formatlibrary.com. Spotted an inaccuracy? Flag it in the Tengu forum — sourced change requests get reviewed.