If the answer is no, AoE almost AUTOMATICALLY kills Animal Companions. A level 5 Animal Companion (let's say a wolf) has 20 HP and +2 Dexterity Save. A level 5 wizard's Fireball does 8d6 Dmg (average of 28 damage). The save DC will probably be at least 14. So the pet has a less than 50% chance of not being incinerated by it. And if the wizard's damage roll is high, even MAKING the save it could die, or be a few HP away from death.
This is why 3.5 had animal companions and familiars with Improved Evasion. The simpler 5e rules don't cover that.
The wolfs save is 15 as it adds rangers prof mod.
There is another important issue regarding the Animal Companion. A GM on here dismissed concerns of an animal companion's fragileness out of hand by saying "the monsters will focus on attacking other things". Okay. Does the monster's breath weapon carve out a nice bubble to not hit the Ranger's adjacent Animal Companion? Does the enemy wizard's fireball also likewise spare the poor pet. I'm assuming the answer is "no".
If the answer is no, AoE almost AUTOMATICALLY kills Animal Companions. A level 5 Animal Companion (let's say a wolf) has 20 HP and +2 Dexterity Save. A level 5 wizard's Fireball does 8d6 Dmg (average of 28 damage). The save DC will probably be at least 14. So the pet has a less than 50% chance of not being incinerated by it. And if the wizard's damage roll is high, even MAKING the save it could die, or be a few HP away from death.
It's also bad for a character concept having "disposable pets". Imagine the ranger's story: "I have my loyal wolf named Whisper. He's been my truest friend since childhood when I grew up among the people of the high steppes. In my background, he played a vital and important role on our previous adventures for years. But he died on my first adventure where I was a playable character. So I replaced him with Skippy the wolf. He died the next day. So I replaced him with Toby the mastiff. Wolves just wouldn't bond with me anymore for some reason. Toby bit the dust a few days later. That's when I got the next Mastiff. I didn't bother naming it this time. The kennel owner began offering a discount. Unfortunately the mastiff died, too. So now, I'm trying to lure an animal towards our camp so I can have another disposable companion for tomorrow's foray into a dungeon..." This is D&D, not Knights of the Dinner Table!
The pets SHOULD NOT BE DISPOSABLE. It wrecks character concept. It's your animal companion. By RAW, you replace them all the time (and you'll have to based on their durability)... why bother even naming them?
The pet should be durable, and not easily replaced. It should be an important part of your character.
There is another important issue regarding the Animal Companion. A GM on here dismissed concerns of an animal companion's fragileness out of hand by saying "the monsters will focus on attacking other things". Okay. Does the monster's breath weapon carve out a nice bubble to not hit the Ranger's adjacent Animal Companion? Does the enemy wizard's fireball also likewise spare the poor pet. I'm assuming the answer is "no".
If the answer is no, AoE almost AUTOMATICALLY kills Animal Companions. A level 5 Animal Companion (let's say a wolf) has 20 HP and +2 Dexterity Save. A level 5 wizard's Fireball does 8d6 Dmg (average of 28 damage). The save DC will probably be at least 14. So the pet has a less than 50% chance of not being incinerated by it. And if the wizard's damage roll is high, even MAKING the save it could die, or be a few HP away from death.
It's also bad for a character concept having "disposable pets". Imagine the ranger's story: "I have my loyal wolf named Whisper. He's been my truest friend since childhood when I grew up among the people of the high steppes. In my background, he played a vital and important role on our previous adventures for years. But he died on my first adventure where I was a playable character. So I replaced him with Skippy the wolf. He died the next day. So I replaced him with Toby the mastiff. Wolves just wouldn't bond with me anymore for some reason. Toby bit the dust a few days later. That's when I got the next Mastiff. I didn't bother naming it this time. The kennel owner began offering a discount. Unfortunately the mastiff died, too. So now, I'm trying to lure an animal towards our camp so I can have another disposable companion for tomorrow's foray into a dungeon..." This is D&D, not Knights of the Dinner Table!
The pets SHOULD NOT BE DISPOSABLE. It wrecks character concept. It's your animal companion. By RAW, you replace them all the time (and you'll have to based on their durability)... why bother even naming them?
The pet should be durable, and not easily replaced. It should be an important part of your character.