Dragon Ball Super made it clear that Android 18 is several levels below Android 17 now. In Dragon Ball Z, the two were shown to be on an equal playing field. During their first story in the anime, 17 and 18 battled hard against Super Saiyan Vegeta and Piccolo respectively, with both villains proving to be formidable opponents.
Since then, both characters have gone through some notable evolutions. At this point in the franchise, Android 17 and 18 have left their villainous roots far behind them. In Dragon Ball Super’s Tournament of Power, the brother-and-sister duo fought on Goku’s Universe 7 team and managed to work together effectively. In fact, 17 proved to be so powerful that he lasted until the end of the tournament. When Goku and Frieza sacrificed themselves to take out Jiren, Android 17 was left as the last fighter standing – and in turn, the winner of the tournament. What he was able to accomplish would never have been possible if he hadn’t made some shocking, off-screen gains. His fight with Goku proved that the character is currently Super Saiyan Blue-level.
Meanwhile, 18 hasn’t been able to match her brother’s impressive progress. Her fights in the Tournament of Power weren’t a clear indicator of where she sits on the power scale, but her failure to beat Majora (who was defeated by Krillin) created the impression that though she is stronger than her husband, Krillin isn’t that far behind her. That means 18 is now grouped with the weaker Z-Warriors, whereas 17 is up there in the same class as Gohan and Piccolo. 18’s failure to climb as high as 17 in Dragon Ball Super can most likely be attributed to the differences in their lifestyles. It seems that 18 has simply put less time and effort into her training.
Many of 18’s appearances in Dragon Ball Super have suggested that she spends most of her time with her husband and daughter. Ever since marrying Krillin, Android 18 has embraced her humanity. And though she has maintained her toughness, she rarely takes part in the action. 17, on the other hand, has kept himself busy as the protector of an island. Goku finding 17 and immediately becoming embroiled in a fight with aliens over the island’s animals provided viewers with a taste of what 17’s everyday life is like. Plus, 17’s ability to keep up with Goku was a sign that he trains regularly.
Thanks to his continuous efforts to protect his island, Android 17 gained enough strength to become the breakout star of Dragon Ball Super’s Tournament of Power and one of the saga’s biggest surprises. With the power he possesses, he could be one of the first Goku calls on the next time trouble arrives at their doorstep. Of course, that’s not to say that Android 18 isn’t a force to be reckoned with in her own right. She’s no longer in the same league as her brother, but is still a bit stronger than Krillin, Tien, and Yamcha.