What is the Meaning of Bonus HD?

[bassmike7021]

Hey guys!

I'm new in D&D and I have a question about bonus HD.

I play a half elf druid and I want to make the adjustments to my animal companion according to this table:
http://www.d20srd.org/srd/classes/druid.htm#theDruidsAnimalCompanion (http://www.d20srd.org/srd/classes/druid.htm#animalCompanion)
The only thing that I dont understand how it works is the Bonus HD.
The table says that if I am 6 level Druid, my companions gains +4 bonus HD.

What that means? Does it mean that the dice I roll to determine the hit points of my animal is 1d(8+4) = 1d12?

Help me plz!

[LTwerewolf]

No, it means that your companion gets an additional 4d8 hp, along with the attack bonus, saves, skills, and feats.

[Chaosvii7]

For further information, direct your attention to Urpriest's guide on monstrous classes here (http://www.giantitp.com/forums/showthread.php?t=207928), which discusses in better detail what HD means and what advancement means.

You animal companion starts with a base form and gains additional benefits in the form of Racial Hit Dice, which give them abilities comparable to an NPC class(as Racial Hit Dice are supposed to be).

Basically, take the base animal form presented in the Core Rulebook and add 4d8 to it - this means giving it hit points, increasing skill points(if relevant), giving it feats(if it gets one at that level), increasing base saves and base attack bonus.

[Telonius]

It's basically giving them a level in "Animal."

So let's say your animal companion is a camel (http://www.d20srd.org/srd/monsters/camel.htm). When you're a first-level Druid, you use the stats in the Monster Manual, which means it already has three hitdice. (You can tell this because it has 3d8+6 hitpoints). When you level up to Druid3, the camel gains an extra two hitdice. It gains BAB, base saves, and skills as though it had taken two more "levels in Animal (http://www.d20srd.org/srd/typesSubtypes.htm#animalType)." With each "level," you get:

d8+Constitution hitpoints
3/4 Base Attack (i.e. the same base attack as a Cleric of equal level)
Good Fortitude and Reflex Saves, poor Will Save
2+Int skill points (minimum 1)
Feats if applicable

So, adding that to the Camel, you'd get:
5d8+10 hitpoints
BAB 3, which takes his attack bonus to +1 for a Bite attack
Base saves: Fort +4/Ref +4/Will +1, which makes the total saves Fort +6/Ref +7/Will +1.
2 more skill points. A Camel already has three ranks each in Listen and Spot, which are the Camel's "class skills."
The camel already had three "levels in animal," so it doesn't get another feat until it gets to 6.

You also get other bonuses like increases to strength and dexterity (note that these can affect attack, AC, and Reflex saves). But those bonuses are special Animal Companion bonuses, not based on the animal's hitdice.

[bassmike7021]

Thnx to everyone for replying! :)

I've read the Urpriest's guide on monstrous classes, but not all things are clear yet.
So, let me see if I get some things:

Let's say I have a wolf (http://www.dandwiki.com/wiki/SRD:Wolf).

Some stats:
HD: 2d8+4
AC: 14
STR: 13
DEX: 15
CON: 15
Attack (+3) 1d6+1.

When my druid will get to lvl 6 the wolf's size will advance from Medium to Large (Str+8, Dex-2, Con+4, NatArmor+2) according to the table from MM, page 291. Its new stats:
HD: 6d8+12 (+4 bonus HD)
AC: 20 (+2 Natural Armor from MM p291, +4 from this table (http://www.d20srd.org/srd/classes/druid.htm#theDruidsAnimalCompanion))
STR: 23 (+8 from MM p291, +2 from this table (http://www.d20srd.org/srd/classes/druid.htm#theDruidsAnimalCompanion))
DEX: 15 (-2 from Advancement, +2 from this table (http://www.d20srd.org/srd/classes/druid.htm#theDruidsAnimalCompanion))
CON: 19 (+4 from table from MM, page 291)

Are these numbers correct? They seem a bit too much to me :P

Also, what happens with the Saves? Is there a table to say how are these upgraded?

Also again, what happens to the base attack? The full attack becomes:
(+?) 1d8+?

[KillianHawkeye]

When my druid will get to lvl 6 the wolf's size will advance from Medium to Large (Str+8, Dex-2, Con+4, NatArmor+2) according to the table from MM, page 291.

No, the bonus HD granted from the Druid's animal companion feature are not the same as normal advancement for the creature. You do not get the size increase, just flat Hit Dice (and other bonuses as listed on the animal companion table). Aside from the listed animal companion bonuses, the creature is like a completely normal member of its species.

[Rhynn]

From the SRD, under Druid, under Animal Companions:


Bonus HD: Extra eight-sided (d8) Hit Dice, each of which gains a Constitution modifier, as normal. Remember that extra Hit Dice improve the animal companion’s base attack and base save bonuses. An animal companion’s base attack bonus is the same as that of a druid of a level equal to the animal’s HD. An animal companion has good Fortitude and Reflex saves (treat it as a character whose level equals the animal’s HD). An animal companion gains additional skill points and feats for bonus HD as normal for advancing a monster’s Hit Dice.

Animal companions, etc., do not increase in size. Size increases are only for "naturally bigger" monsters created by the DM.

Your example wolf would get +4 bonus HD, +4 natural armor adjustment, and +2 Str and Dex. It would have HD 6d8+12, Str 15, Dex 17, AC 19. It would have BAB +4 (for a total attack bonus, sans feats, of +6, damage 1d6+3), and saves Fort +7 (base +5), Ref +8 (base +5), and Will +3 (base +2, Wis 13).

[bassmike7021]

It would have BAB +4 (for a total attack bonus, sans feats, of +6, damage 1d6+3), and saves Fort +7 (base +5), Ref +8 (base +5), and Will +3 (base +2, Wis 13).

Could you explain plz to me how are the saves determined? I mean the +5,+5,+2...

[Greenish]

Could you explain plz to me how are the saves determined? I mean the +5,+5,+2...It has 6 Animal (http://www.d20srd.org/srd/typesSubtypes.htm#animalType) Hit Dice, which have Good Fort and Ref saves, and Poor Will Save, just like, say, a Ranger (http://www.d20srd.org/srd/classes/ranger.htm).


Do read Urpriest's guide linked in the third post.

[Karnith]

Could you explain plz to me how are the saves determined? I mean the +5,+5,+2...
Animal hit dice (http://www.d20srd.org/srd/typesSubtypes.htm#animalType) give a creature two good saves (Fortitude and Reflex), and one poor saving throw (Will). You can find the good and poor saving throw progressions by referencing character classes (a Barbarian, for example, has a good Fortitude save and poor Reflex and Will saves) for saves at equivalent HD, or you can follow the general formula for saves, which is that good saves equal (HD/2)+2, and that poor saves equal (HD/3).

So a wolf animal companion at 6 HD has base Fortitude and Reflex saves of (6/2)+2=3+2=+5, while it has a base Will save of 6/3=+2.

EDIT: I would also highly recommend reading Urpriest's guide, as it's pretty comprehensive.

[Rhynn]

Could you explain plz to me how are the saves determined? I mean the +5,+5,+2...

The rules are pretty clear: "An animal companion has good Fortitude and Reflex saves (treat it as a character whose level equals the animal’s HD)." But then, IMO, the rules in the PHB/SRD were pretty clear (except on the size increase issue) all over.

There's two types of save progressions, good and bad. The druid's table is the closest, and there you can see that at level 6 (6 HD), the good base save is +5 and the bad is +2.

Thus, a 6 HD animal has good saves (Fort and Ref, as the rules quote says) at +5, and poor saves (Will) at +2. Plus ability modifiers and other bonuses.

[bassmike7021]

All of you have been very helpful!

I thank you for the answers and I'm sorry for taking your time :)

[lunar2]

jst want to point out that it gets more complicated if you have a dire animal companion, since the rules say in one spot that they advance as normal (all good saves) but also says they only get good fortitude and reflex saves. if you have a dire animal as an animal companion, ask your DM about that. also if you have an animal companion that is not an animal, which you can do with certain books. non-animal animal companions run into the same issue as dire animals.