SEOUL, July 7 (Yonhap) -- Rock has long been the genre that lets Kihyun sing with ease. But on the upcoming new album "Borderline," he deliberately moved away from comfort, choosing a lead track that is still rock-based but far more demanding, with a pronounced arc and soaring high notes.

The choice, he said, was driven by a desire to avoid repeating himself and to show a different side of his voice, even if it meant facing some fear.

"I spent a lot of time thinking about what else I should show for my third release," the Monsta X vocalist said in a group media interview in Seoul on Wednesday. "I felt it was time to show who I really am."

Kihyun debuted in 2015 as Monsta X's main vocalist and quickly became known for his powerful delivery and wide vocal range. He launched his solo career in 2022 with the single album, "Voyager," followed by the first EP, "Youth."

Monsta X's Kihyun is seen in this photo provided by Starship Entertainment. (PHOTO NOT FOR SALE) (Yonhap)

For his second solo EP, "Borderline," set for release Tuesday at 6 p.m., Kihyun said he wanted to avoid simply repeating the high energy of his previous releases.

"The first two solo songs were fun and easy for me to sing and enjoy on stage," he said. "But this one is not like that. It has a rock base, but it also has lyrical parts and explosive moments, so it has a full emotional arc."

That complexity, he said, made the album's lead track, titled "So Good," both intimidating and rewarding.

"I had been avoiding that kind of song in some ways," he said. "Even though I like rock, I was worried it might bring back the pressure I used to feel. But now that I have recorded it, I feel like I have broken through my limits."

That need for change also shaped the album's title. "Borderline" refers to crossing a line by his own decision, Kihyun explained, whether that line leads to something good or bad.

"This album was made entirely according to my own will -- from the characteristics of the tracks and the selection of the lead track to the overall direction, not a single detail was left without my opinion," he said.

In that sense, he considers the album to be genuinely his own.

"It feels like with this album, my own distinct color has finally been clearly established," he said, after sharing how he has experimented with various singing styles and vocal techniques throughout his solo career. "Although I cannot articulate it in a single word, I feel this album firmly captures and gives a name to the color of my vocals for the first time in my 11-year career."

Monsta X's Kihyun is seen in this photo provided by Starship Entertainment. (PHOTO NOT FOR SALE) (Yonhap)

He also expressed his strong affection for "So Good," which he first heard last December during the group's participation in the 2026 iHeartRadio Jingle Ball Tour in the United States, when a local promoter played it for him.

"I have always liked Britpop and modern rock," he said. "When I heard it, it immediately reminded me of the feeling I get from the intros of British singer James Bay's songs. From that moment on, it stayed in my head."

Also on the seven-track album are "Borderline," "Stealin' Air," "Domino," "Lazy Day," "Late Night Drive" and "Howling."

Kihyun said the record is built around rock, but it also stretches into other textures, varying the refreshing feelings, tempo and lyricism from track to track.

He also experimented a lot on the record -- featuring songs with R&B elements, rap parts and even some jazzy touches -- despite admitting that R&B is a genre he said he neither likes nor is good at.

Monsta X's Kihyun is seen in this photo provided by Starship Entertainment. (PHOTO NOT FOR SALE) (Yonhap)

The 32-year-old said the K-pop industry has changed a lot since his debut as Monsta X, especially in song length, fan habits and the pace of promotion.

"When we debuted, albums often had four-minute songs, sometimes even five," he recalled. "Now my solo title track is in the 2 minute 40 second range."

He said listeners have also become more open to experimentation. "Before, if artists tried something different, people were a bit more guarded," he said. "Now they seem more willing to listen, and that's a good thing."

Promotions now come with far more content demands than before, he added. "It's incredibly busy these days," he said. "When we go on tour, we film vlogs in the morning while getting hair and makeup done, we shoot short-form challenges, we do short livestreams. Fans know my daily life so well now! It was difficult for me to get used to it at first after being discharged from my military service, but now I think I've fully adapted."

He returned from his 18 months of mandatory military service in February 2025.

Even with those changes, he said the goal remains simple: make music that lasts.

"I'd really like the song to rank high on the charts," he said. "Not necessarily No. 1, 2 or 3, but I hope it can stay within the top 50 for a long time, because it needs to survive on the charts to let people know what kind of music I make."