I think I figured some stuff out. It seems like when things scream and attack me(elves in darsylon) and I berserk it doesn't give fury of the clan as if I was not fighting.

866/1019h(84%) 356/386m(92%) 785/785v 10 AM civilized full 16267tnl>
You dodge an elven wine merchant's slice.
You can't see a thing!
Someone's kicked dirt scratches you.
You parry someone's stab.
You parry someone's stab.
Someone dodges your wrath.
Your wrath DISMEMBERS someone!
Your wrath MANGLES someone!
Someone is covered with bleeding wounds.

863/1019h(84%) 356/386m(92%) 785/785v 10 AM civilized full 16267tnl> You can't see a thing!
Someone is covered with bleeding wounds.

863/1019h(84%) 356/386m(92%) 785/785v 10 AM civilized full 16267tnl> You are already being as intimidating as you can.
Someone is covered with bleeding wounds.

863/1019h(84%) 356/386m(92%) 785/785v 10 AM civilized full 16267tnl> ber
Your pulse races as you are consumed by rage!
Someone's slice MUTILATES you!
You parry someone's stab.
Someone dodges your wrath.
Someone meets your wrath with a resounding impact.
Someone is covered with bleeding wounds.

Orcs who use this skill in the midst of combat against a powerful enough foe

That would be the main reason that berserk would just look like normal.