Is that scottish, or irish, or what they call gaelic i think is the spelling?
Nightwish is ... complex. The founding members of the band -- Tuomas (keyboards, band's composer), Marco (bass, backup vocals, lead vocals), Kai (drums), and Emppu (lead guitar)-- are Finnish, the (primary) lead vocalist -- Floor -- is Dutch, and their pipes/woodwinds/third guitar/backup vocals/lead vocals/what the hell can't he do -- Troy -- is British.
The band's first lead singer -- Tarja -- had a haunting ethereal operatic voice with the rhythm of an epileptic when performing live. Their second lead singer -- Annette -- had a voice more suited to pop music. Most fans of the band disliked her even though some of their best songs -- Amaranth, Storytime, Song of Myself -- come from that time.
Floor can sing almost anything in any style. She can do the head voice classical, mix, chest belts, growls, full on operatic, pop, rock...
Recently (5-6 years ago) their old drummer Jukka had to step down due to a sleep disorder. Care to guess which one? The new drummer -- Kai -- is more versatile, but he lacks the energy Jukka had.
Basically they've had a lot of lineup changes the past 20 years.
If you liked that song, you should probably check out the acoustic version with just Floor and Troy on Planet Rock.
https://www.youtube.com/watch?v=yYtkPpFYzOoThough the gateway that brings most people into Nightwish is the Wacken performance of "Ghost Love Score".
https://www.youtube.com/watch?v=JYjIlHWBAVoFirst song of theirs I remember encountering was "Wishmaster", though my favorite is a tossup between "Nemo" and "The Islander". The latter being interesting because it has Marco singing lead.
Nope, not a fan. Not at all.