Is Slaine more of a UK thing?
Slaine (I think most of us pronounce it 'slain', but I seem to remember the Gaelic pronunciation should be something like 'slawnye') first appeared in 2000AD back in the 80's and was a unique story from the off, being set in the far past, in an undetermined prehistoric 'Time of Legends' in the lands that would later separate into Ireland, Britain and western France. All the other stories in 2000AD were futuristic sci-fi and there was this weird 'sword and sorcery' thing popping up, based loosely around 'Celtic' mythologies but with some wonderful original storylines built in. As Manic Miner says, they are thoroughly recommended, especially if you go through them in chronological order. There have been lots of different artists who worked on Slaine over the years, all of them creating unique flavours, and everyone will have their own taste as to which ones they like best - I won't be tempted to steer the conversation into
that arena, because that's a thread in its own right, and one that must surely flame into open war!