On the map of the Stilshrine of Miriam, you can see where they are pointing to and where they are. Then go back to the room where Darkmare appeared and run through there and through the door to fight Mateus.

Quickening Chain at start when all Ice Azers close > Thundara on ice Acers.

If you do use Thundara instead, watch out cause Mateus had reflect.

If you use a Quickening chain try for a concurrence (Inferno,Torrent,Ark Blast ETC.) as they will hit the Ice Azers.

Good Luck...

Ultima, The High Seraph