Unfortunately, it appears there is no singular Death Attack special, so you need to create a script that includes all possible class specials and specials that could qualify. If you are only using it for yourself, you wouldn't necessarily need to do more than you need, though. The script below would need to run post-levels.
Code:
hero.childfound[cAsnDeath].tagis[Helper.ShowSpec] + hero.childfound[cDStDeath].tagis[Helper.ShowSpec] <> 0
You can add as many lines as you like for additional class specials / specials.