Hello, my method: dig a deep and wide enough trench around the altar. Within range of your bow, use the hoe to create a wall behind which you can hide and place the transmitter. From the moat, lead a short channel in your direction. Out of 4 actions, Yagluth stayed 2 times in the channel and 2 times on the sacrifice, and if I didn't significantly reveal myself from behind the wall, he just stood and stared stupidly. I think I used about 300 ice arrows, silver, iron work. It takes longer than it is after, you need to get a second bow or repair it. Quite calmly, it can be regenerated at the base using a transmitter.
I used a translator, so excuse any mistakes.