Book 1 introduces most of the cast, but, as people have noted, Harry tends to revisit stuff in later books whenever he meets people
About the only thing I can entirely say you're missing in book 1 that's essential is Harry's initial meeting with Bianca, which lays down a little foreshadowing for the events of Book 3. Beyond that, the first two books are very standalone and can be skipped over, though I found them great reads in general. But Book 3 is Very Important due to the Party Of Chekov's Arsenal. Some of it may be retroactive, but Butcher's pulled out Chekov's Guns from that sequence that're still going off eight books later.
---
"Oh, silver blade, forged in the depths of the beyond. Heed my summons and purge those who stand in my way. Lay
waste."
About the only thing I can entirely say you're missing in book 1 that's essential is Harry's initial meeting with Bianca, which lays down a little foreshadowing for the events of Book 3. Beyond that, the first two books are very standalone and can be skipped over, though I found them great reads in general. But Book 3 is Very Important due to the Party Of Chekov's Arsenal. Some of it may be retroactive, but Butcher's pulled out Chekov's Guns from that sequence that're still going off eight books later.
---
"Oh, silver blade, forged in the depths of the beyond. Heed my summons and purge those who stand in my way. Lay
waste."