Hi, I'm creating a Vampire Feat and I'm trying the Bite attack as an action. The attack does 1d4+STR piercing damage in addition to 3d6 necrotic damage.

As it is impossible to add two damages to one action (as far as I know, please let me know if I'm wrong), I decided to created two actions instead.

However, the necrotic action automatically adds my strength character's modifier to the attack, making it show 3d6+4 on my character sheet instead of just 3d6.

Here is what I added to the Feat Action:

• Action type > General
• Is proficient > Yes
• Dice count > 3
• Die type > d6
• Damage type > Necrotic
• Display as Attack > Yes
• Affected by martial arts > Yes
• Activation type > Action

 Thank you in advance for any help! x

Bite. (Bat or Vampire Form Only). Melee Weapon Attack: +9 to hit, reach 5 ft., one willing creature, or a creature that is grappled by the vampire, incapacitated, or restrained. Hit: 7 (1d6 + 4) piercing damage plus 10 (3d6) necrotic damage. The target’s hit point maximum is reduced by an amount equal to the necrotic damage taken, and the vampire regains hit points equal to that amount. The reduction lasts until the target finishes a long rest. The target dies if this effect reduces its hit point maximum to 0. A humanoid slain in this way and then buried in the ground rises the following night as a vampire spawn under the vampire’s control.