I accidentally gave my bearded giant a thornheart instead of the village outer giant and somehow I kept hitting Andaayhn via the autoassist. This happened three or four times till we got it killed.

<926/926(100%hp) 806/1067(75%)m 79%mv 22700tnl> <clear waning> <civilized outdoor 11 PM>
A bearded forest giant falls flat on his face.
A bearded forest giant's bash misses Andaayhn.
Andaayhn's flaming bite *** DEMOLISHES *** a bearded forest giant!
A rainbow of colors shoots out from Andaayhn's hand.
An indigo beam of light hits a bearded forest giant!
Andaayhn's prismatic spray MASSACRES a bearded forest giant!

<926/926(100%hp) 806/1067(75%)m 79%mv 22700tnl> <clear waning> <civilized outdoor 11 PM> autoassist
You will now assist when needed.

<926/926(100%hp) 806/1067(75%)m 79%mv 22700tnl> <clear waning> <civilized outdoor 11 PM>
Andaayhn stops following you.
Andaayhn now follows you.

<926/926(100%hp) 806/1067(75%)m 79%mv 22700tnl> <clear waning> <civilized outdoor 11 PM>
Andaayhn stops following you.
Andaayhn parries your divine power.
Andaayhn's flaming bite misses a bearded forest giant.
Andaayhn's flaming bite MASSACRES a bearded forest giant!
Andaayhn is in perfect health.

>I accidentally gave my bearded giant a thornheart instead of
>the village outer giant and somehow I kept hitting Andaayhn
>via the autoassist. This happened three or four times till we
>got it killed.

You keep autoassisting the one member that is still in your group (the giant that you attacked), which is fighting against Andaayhn. The safest thing to do in that situation is flee and regroup.