In the Dragon Ball franchise, humanity has long been passed over in terms of power. In a world filled with impossibly strong androids and aliens like the Saiyans and Namekians, it can be tough for a regular human in that world of fighters.
Despite that, two humans, Krillin and Tien have stayed at the forefront of the battles that defined Dragon Ball Z. Even though they've never fought each other directly, we're going to take a closer look at both fighters to see which one of Earth's toughest human champions is really stronger.
KRILLIN
In the original Dragon Ball. Krillin was initially introduced as a rival for the young Goku. They trained together under Master Roshi, but over time, the two became lifelong friends. Although his power level has never been able to keep up with that of Goku (which he is painfully aware of,) he's never backed down from a fight. This attitude has cost Krillin his life multiple times across the course of the franchise, against foes like King Piccolo's son Tambourine, Frieza and Buu. Still, his quick-thinking and unique power set have allowed him to survive many more battles impressive than most might expect. He survived the Saiyan attack, kept Frieza's Second Form at bay while Goku healed on Namek, held his own against Imperfect Cell and survived a direct hit from Perfect Cell. He's even found love on the battlefield, eventually winning the heart of the (initially antagonistic) Android 18 and raising a child with her.
Trained by Master Roshi, Krillin is capable of using moves created by other martial artists, such as the Solar Flare and Kamehameha. He also has a number of abilities that are unique to him. His Scatter Bullet shoots a large blast into the air that then separates into multiple smaller and faster blasts, allowing him to cover a wider range or target multiple enemies. His Jumping Energy Wave allows him to clear attacks with ease, and his most distinct power is the Destructo Disc, a razor-sharp energy disc that can cut through almost anything.
TIEN
Tien was the star student of Tsuru-Sen'nin, the long-time rival to Master Roshi. Like his best friend Chaozu, he was initially an antagonist in Dragon Ball who debuted during the 22nd World Martial Arts Tournament, competing against Goku and his friends. Tien was even victorious in his fight with the heroes, breaking Yamcha's leg and eventually defeating Goku in the final match. But along the way, he came to respect Goku, especially after their friends Krillin and Chaozu were killed. They fought alongside each other against King Piccolo, cementing their friendship for life. He took part in many of the battles in Dragon Ball Z, although he died while going up against Nappa and Buu. But, like Krillin, he's never let himself give up.
Since Tien wasn't trained by Master Roshi, his abilities differ from other heroes like Goku, Krillin and Yamcha. He's capable of the Dodon Ray, a powerful blast from his finger. He also has the blinding Solar Flare, the Four Witches Technique that gives him another set of arms and the Multi-Form, which allows Tien to make four identical copies of himself to strike from multiple directions at once in battle. However, His most powerful signature moves is the Shin Kikohou, the Tri-Beam. While it's powerful enough to hold massive threats like Semi-Perfect Cell at bay, it also has a major cost. Using it too much drains the life-force from Tien, and it can even kill him. Tien's first death even came as a result of using the technique to try (and fail) to kill Nappa.
IS TIEN STRONGER THAN KRILLIN?
By this point in the Dragon Ball saga, both Krillin and Tien have been dramatically outclassed by the franchise's powerhouses. The fact that neither of them can keep up with the likes of the Saiyans doesn't keep them from being skilled fighters, however. Both of them still prove to be creative combatants, using technique and strategy to overcome stronger enemies and stay alive through most of the franchise. For both warriors, this is probably best on display during the Cell Saga in Dragon Ball Z and the Tournament of Power during Dragon Ball Super. Going up against the Androids and Cell was almost impossible for either of them, but Krillin still proved capable of surviving a hit directly from Perfect Cell while Tien held Semi-Perfect Cell at bay (almost at the cost of his life) using the life-draining Shin Kikohou.
Meanwhile, both of them served as members of Team 7 during the multiversal Tournament of Power. Although Krillin was eliminated from the Tournament before Tien, he was able to bring down three opponents as opposed to Tien's two. Tien was also the next hero to be knocked out of the battle after Krillin. While Tien might have more technically powerful moves, they come with a cost that Krillin doesn't have to risk. Meanwhile, Krillin has more creative abilities and clever tactics, along with more experience going up against tougher enemies and (barely) surviving.
If the two came up against one another, Krillin could probably out-maneuver Tien. While we may never know for sure until they come to blows, Krillin is arguably the better fighter out of the two of them, and arguably the stronger of the two since he had his potential unlocked on Namek. But while Krillin found peace in the early days of Dragon Ball Super, Tien's training never really stopped. Even if that means that Tien might actually be a bit stronger at this point, strength doesn't always guarantee a win in Dragon Ball.