Drazas answer is not exactly accurate.
They start like this:
Battle Defense ------ Trains the creature in the disarm and paralyze special moves. Also trains the creature in the Heightened Senses & Shield Bash mastery abilities.
You have to tell the pet to Guard you to activate Body Guard.
Body Guard on pets cuts the damage taken by 50% for pet and owner. (It is not the same as the one Toons can get.)
I made one to test it. The Ram had 3 Greater Dragons on it and it needed very little help with HP.
If you put any other magic on you lose all but LL.
A Ram does not have Wrestling Mastery.(which also gives paralyze and disarm) Not all pets can get Battle Defense.
Battle Defense on pets is kind of like Parry Mastery on Toons.
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Parry This describes the way it works on Players not pets. But pets get these in their own way.
Title: The Deflector
Shield Bash When activated the shield user will execute a shield bash on successfully hitting or parrying their opponent causing physical damage and paralyzing their opponent, interrupts spells if players are not immune to paralyze, based on parry skill, best weapon skill, and mastery level. Damage is capped in pvp at 35.
Body Guard The shield user chooses a protectee to absorb a percentage of damage done to the protectee based on parry skill, best weapon skill, and mastery level.
Heightened Senses Toggle ability that provides the Parrying Master with increased chance to parry based on parry skill, best weapon skill and mastery level that consumes mana while active.
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I do not know the damage values for Shield Bash or the parry gained with Heightened senses.
Body Guard (when active) on pets does not split the damage. The pet and owner receive 50% less damage taken. If the pet is the only thing taking damage the owner takes no damage.
This 50% works for melee and spell damage. I have tested Body Guard on my toon in Fel with melee and spell damage.
Shield Bash When activated the shield user will execute a shield bash on successfully hitting or parrying their opponent causing physical damage and paralyzing their opponent, interrupts spells if players are not immune to paralyze, based on parry skill, best weapon skill, and mastery level. Damage is capped in pvp at 35.
Body Guard The shield user chooses a protectee to absorb a percentage of damage done to the protectee based on parry skill, best weapon skill, and mastery level.
Heightened Senses Toggle ability that provides the Parrying Master with increased chance to parry based on parry skill, best weapon skill and mastery level that consumes mana while active. 