You can do the “Strongest in the World” side quest after reaching the Akkala region in Zelda: Tears of the Kingdom.
Although you can select this quest at any given point in the game, it is recommended that you start it during the later stages of the game. The side quest revolves around the use of Link’s weapon-fusing ability which intrigues Chabi who is a Hylian traveler in Zelda.
She dreams about creating weapons out of Lynel Horn. Since she is not able to do it by herself, she asks Link to aid her fulfill her dream.
How to start Strongest in the World in Zelda: TotK
Make your way to the eastern parts of Deep Akkala to reach the East Akkala Stables. If you have taken our recommendation to this side quest in the latter stages of the game, you will be able to fast travel here.
Simply fast travel to the Jochi-iu Shrine. The stables are just nearby. You will find Chabi at the back of the stables. Speak with her to start the “Strongest in the World” quest in Tears of the Kingdom.
She will assign you a task to craft a weapon from Lynel horn and since this side quest doesn’t have any specific requirements, you will start the quest as soon as you talk to Chabi at the coordinates 4205, 2763, 0126 as marked on the Zelda map above.
How to complete the Strongest in the World in Zelda: TotK
Since Chabi wants you to craft a weapon from Lynel horn, you must defeat the creature known as Lynel to acquire the necessary material to use your weapon-fusing ability.
Lynel is one of the hardest mini-bosses to defeat in Hyrule. It is a mythical creature that comes in different forms. The one you will be fighting will be the Red Lynel who is found at the North Akkala Valley as shown in the Zelda map below:
As you approach the beast, it will have two main attacks in its arsenal called Contact and Sword Throw. You can dodge these attacks by simply moving sideways.
As you dodge the attacks, you must follow up by slashing the knees of the beast and then moving away as it executes one of its attacks. Follow this process until the mini-boss is defeated.
Collect 1x Lynel Saber Horn, 1x Lynel Mace Horn, 1x Soldier’s Claymore, 1x Lynel Box and 1x Lynel Hoof, the mini-boss drops.
Use your Fuse ability to combine one of the weapons with the Lynel Horn and return to the East Akkala Stable to talk to Chabi and complete the Strongest in the World side quest in Zelda: TotK