The creature gains four claw attacks, each using its base attack bonus + its Str modifier for attack rolls. Each claw deals 1d4 points of damage + the subject's Str modifier, and if an opponent is struck by two or more claws in 1 round, the subject can rend it for an additional 2d4 points of damage + 1-1/2 times its Str modifier.
A creature cannot use normal weapons and the claw attacks in the same round, and the subject does not gain additional claw attacks from a high base attack bonus.1
The rules are very clear:
Your BAB is +13, your strength is +3. So you roll your attacks before any other modifiers are +16/+16/+16/+16, as that is exactly what the paragraph above calls out as your attack roll.
- due to half the arms being secondary2, the GM might demand to include the -5 on them, for a +16/+16/+11/+11 - it is unlikely if that is meant to be the case though, as the spell explicitly called out four attacks at BAB + Str.
- you can not use any other attacks gained from high BAB.
Each hit rolls for 1d4+3 as the basic claw damage.
If two or more claws hit, you roll additionally a single 2d4+4 (half get rounded down).
So the total damage is:
| Number of claw attacks hit |
composition of damage |
total damage dealt |
| 0 |
0 claws + 0 rending |
0 |
| 1 |
1d4+3 claws + 0 rending |
1d4+3 |
| 2 |
2d4+6 claws + 2d4+4 rending |
4d4+10 |
| 3 |
3d4+9 claws + 2d4+4 rending |
5d4+13 |
| 4 |
4d4+12 claws + 2d4+4 rending |
6d4+16 |
Added Request: Why only one Rending?
There is one part that OP requested further clarification:
if an opponent is struck by two or more claws in 1 round, the subject can rend it for an additional 2d4 points of damage + 1-1/2 times its Str modifier.
That is a simple conditional logic sentence that is best read like this:
- IF [an opponent] is [struck by two or more claws in 1 round]
- THEN [the subject can rend it for an additional 2d4 points of damage + 1-1/2 times its Str modifier.]
- ELSE [nothing]
The condition of [an opponent] being stuck by [two or more claws in 1 round] can only be either True or False. It can not be true multiple times. The effect of the conditional being true also contains a numerical: there is only a single [an additional 2d4 ...]. Would it be wanted to increase the damage per multiple attacks, then it would be worded differently and include such a pointer, such as this:
if an opponent is struck by two or more claws in one round, the subject can rend it for an additional 2d4 points of damage + 1-1/2 times its Str modifier per hitting claw after the first.
Now, the wording in the rule does say you can only rend a single target once a turn. It does not limit rending itself in this way. As long as you land 2 hits on two targets each, you do 4d4+10 to each of them. The two targets may not be the same creature.
Citation notes
- Spell Compendium, p. 106
- see for example here