World Events, Asgard

Approach and talk to the man and then follow him. He will take you to the boar, which will start running away. Chase the boar and kill it to finish this event.

Talk to the man over the well. Choose the second option - "There is nothing for you in Helheim." to end this event without a fight. Otherwise, you will have to fight the man.

Find the cow trapped in the ruins and then destroy the wooden barriers and move the boulder so the cow can go outside.

To complete this event you will need a boat. You can find one for example near Heimdall's Tower. Sail to the island and talk to the man. Then go back to the boat and the man will get on it. Take him to the main island and get ashore.

When you get here, you will see a stag. Follow it, more stags will join you along the way, and eventually they will take you to the chest where you will find Ymir's Tear Stone #27 chest. Open it to finish this event.

Just talk to the man. That's all you have to do.