If you take control of your opponent's face-down "The Legendary Fisherman" with "Change of Heart" while "Umi" is face-up on the field, when it is flipped face-up it is immediately returned to your opponent.

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 Graveyard.

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.

If you control your opponent's "The Legendary Fisherman" with "Snatch Steal" and "Umi" is activated, "The Legendary Fisherman" returns to your opponent. During your opponent's Standby Phases they will still gain 1000 Life Points.

A Legendary Ocean: When "A Legendary Ocean" is active, "The Legendary Fisherman" on the field is unaffected by Spell Cards, so it does not receive the ATK/DEF bonus or have its Level reduced by 1. It still is treated as Level 4 in your hand, so you may Summon it without Tribute.

Big Wave Small Wave: "The Legendary Fisherman" is not destroyed by the effect of "Big Wave Small Wave" if "Umi" is on the field, so he remains on the field.

Command Knight: If "Umi" is active and you have "The Legendary Fisherman" on the field, your opponent can attack directly. But if you have "The Legendary Fisherman" and "Command Knight", and no other monsters, your opponent cannot attack directly because of "Command Knight", and cannot attack "Command Knight" because of his effect, and cannot attack "The Legendary Fisherman", so he cannot declare an attack (but can enter the Battle Phase to activate card effects).

Different Dimension Gate: When you select"The Legendary Fisherman" as a target of "Different Dimension Gate", only the other monster is removed and returns to the field when "Different Dimension Gate" is destroyed.

Dreamsprite: If you control "Dreamsprite", "The Legendary Fisherman", and "Umi" is on the field, "Dreamsprite"s effect can still change an attack target to "The Legendary Fisherman" because he is not being targeted with an attack, but is being targeted with a monster effect.

Ekibyo Drakmord: If "Ekibyo Drakmord" is equipped to "The Legendary Fisherman" and then "Umi" is activated, "Ekibyo Drakmord" will remain meaninglessly equipped to "The Legendary Fisherman".

Guardian Kay'est: "Guardian Kay'est" is not affected by Spell Cards, just like "The Legendary Fisherman".

Maiden of the Aqua: If you have "Maiden of the Aqua" (with her effect active) and "The Legendary Fisherman"on your side of the field, and "Dark Hole" is activated, "The Legendary Fisherman"will not be destroyed.

Mystik Wok: Tributing a monster for "Mystik Wok" is a cost, so you can Tribute "The Legendary Fisherman"

Patrician of Darkness: The effect of "Patrician of Darkness" does not override the effects of"The Legendary Fisherman". You cannot choose an attack target prevented by the effects of these cards. Examples: You cannot choose "The Legendary Fisherman" as an attack target if "Umi" is on the field

Staunch Defender: You cannot select"The Legendary Fisherman" for "Staunch Defender" if cannot be attacked.

The Agent of Force - Mars: "The Agent of Force - Mars" is unaffected by Spell Cards just like "Guardian Kay'est" and "The Legendary Fisherman".