I started rewatching the series and starting to look for feats. Season 1 has been pretty unimpressive so far aside from that statement; which in turn is vague. The Sword of Tengu did disperse a small Tornado, but probably not too impressive. However, there was one good durability feat here. Shredder without his armor or skeleton survived an explosion that completely vaporized a skyscraper. Which sounds like Low 7-B I heard was skyscraper vaporization.
Yeah, the statement alone doesn't imply he oneshots any villages or castles. The Tornado thing is calcable, but I doubt it would exceed Tier 8. But Utrom Shredder surviving the time bomb might be a good feat.
Not sure yet, we could calc the feat of the Sword of Tengu dispersing a Tornado, but should be requested in the calculation request thread first. And Shredder does have one good durability feat here. He survived a blast that vaporized a skyscraper. But other than that, there aren't many feats that exceed Wall level that aren't performed by artifacts in the first 4 seasons.
Edit: Fan of RPGs told me the skyscraper was literally atomized rather than vaporized; vaporizing a skyscraper is Low 7-B and atomizing it would be much higher than that, but it's probably an outlier. "Laying villages to waste" in Ancient Japan would be more like Tier 8. Like 8-C to 8-B range according to him.