A card like ground assault from gatecrash: states ground assault deals damage to target creature equal to the number of land you control.
My question is if there is excess damage does nothing happen or does it go to the player's life?
Another question when a card states that the creature fights another creature ex. Gruul ragebeast: whenever gruul ragebeast or another creature enters the battlefield under your control, that creature fights target creature an opponent controls.
My question is what. When they fight do the creaturto both take toughness away equal to their power or how does it work?
another question regarding a card like gruul ragebeastIsis an ability that starts with whenever, is it a mandatory ability or do you get to choose whether you use it or not?
A card like ground assault from gatecrash: states ground assault deals damage to target creature equal to the number of land you control.
My question is if there is excess damage does nothing happen or does it go to the player's life?
No, you only do what the card says.
Another question when a card states that the creature fights another creature ex. Gruul Ragebeast
My question is what. When they fight do the creaturto both take toughness away equal to their power or how does it work?
Damage does NOT reduce a creature's toughness.
Each creature deals damage to the other equal to its power. If a 2/2 fights a Grull Ragebeast, the Grizzly bears will take 6 and the Ragebeast will take 2. Then the Grizzly bear will be destroyed because it is a 2/2 with at least 2 damage on it.
another question regarding a card like gruul ragebeastIsis an ability that starts with whenever, is it a mandatory ability or do you get to choose whether you use it or not?
If it says "may" it's optional. If it doesn't say "may" it's mandatory.
Another question when a card states that the creature fights another creature ex. Gruul ragebeast: whenever gruul ragebeast or another creature enters the battlefield under your control, that creature fights target creature an opponent controls.
My question is what. When they fight do the creaturto both take toughness away equal to their power or how does it work?
Gruul Ragebeast Each creature will deal damage to the other creature equal to their power, and the damage will be dealt simultaneously. There will be no toughness reduction. Instead, damage will be marked on the creature until the clean up step. If the damage marked on the creature is greater than its toughness, the creature will be destroyed due to state-based actions.
another question regarding a card like gruul ragebeastIsis an ability that starts with whenever, is it a mandatory ability or do you get to choose whether you use it or not?
The words "whenever," "when," and "at" indicate triggered abilities. If the trigger is met, then the ability will trigger. The word you want to look for is "may." If Gruul Ragebeast read, "...you may have that creature fight a target creature an opponent controls," then it would be up to you whether or not you want them to fight. Since it doesn't say "may," though, then it has to happen.
My question is if there is excess damage does nothing happen or does it go to the player's life?
All the damage is dealt to the target creature. For example, if you have 5 lands and target a 1/1 creature, 5 damage is dealt to that creature.
My question is what. When they fight do the creaturto both take toughness away equal to their power or how does it work?
Damage doesn't reduce toughness, rather it is marked on the creature and compared against toughness. Each creature will deal damage to the other, and thus each will mark damage on the other.
For example, if a 3/3 creature fights a 5/5 creature, 5 damage will get marked on the 3/3, and 3 damage will get marked on the 5/5. The 3/3 dies as a result, and the 5/5 lives for now, but the damage remains marked until the end of the turn. A Shock cast later in the same turn can kill the 5/5.
another question regarding a card like gruul ragebeastIsis an ability that starts with whenever, is it a mandatory ability or do you get to choose whether you use it or not?
Gruul Ragebeast 's ability is mandatory. If it was optional, it would use the words "you may".
The words "whenever," "when," and "at" indicate triggered abilities. If the trigger is met, then the ability will trigger. The word you want to look for is "may." If Gruul Ragebeast read, "...that creature may fight a target creature an opponent controls," then it would be up to you whether or not you want them to fight. Since it doesn't say "may," though, then it has to happen.
(Creatures don't have agency. It would be ".. you may have that creature fight target creature an opponent controls." Your wording has a Floral Spuzzem issue.)
The words "whenever," "when," and "at" indicate triggered abilities. If the trigger is met, then the ability will trigger. The word you want to look for is "may." If Gruul Ragebeast read, "...that creature may fight a target creature an opponent controls," then it would be up to you whether or not you want them to fight. Since it doesn't say "may," though, then it has to happen.
(Creatures don't have agency. It would be ".. you may have that creature fight target creature an opponent controls." Your wording has a Floral Spuzzem issue.)