So apparently BTS first Hot 100 entry on the Billboard chart, was at #85 with "DNA" from their "Love Yourself: Her" album.
--- September 25, 2017
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Then 2 months later, they put out a single with Steve Aoki called "Waste It on Me", which placed on the Hot 100 at #89.
--- November 5, 2018
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After, they put out another single "Mic Drop" featuring Desiigner. It debuted at #28 on the Hot 100, becoming the highest charting song by a kpop group, and marked BTS first Top 40 hit on the Hot 100.
--- December 4, 2017
Then, low and behold, BTS have a comeback with their album "Love Yourself: Tear". And their Title track "Fake Love" places at #10.....bro what the heck!!! Only by their next comeback, they ended up in Top 10...!!
--- May 29, 2018
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I'll add this as well, since it was in the same year, 2018. So after BTS Tear comeback, they had ANOTHER comeback shortly after in August with "Love Yourself: Answer", and their Title track "Idol" which featured Nicki Minaj, placed at #11 on the Hot 100.
--- September 4, 2018