The Silverwind Larion comes from ringing the Vesper of the Silver Wind.
To ring the Vesper, you need to rebuild the Crystal Mallet of Heralds with the help of Forgelite Hephaesius.
To build the Vesper, you need to loot 50 Lost Anima Shards scattered across Bastion and the two Bastion dungeons, Necrotic Wake and Spires of Ascension.
45 Shards can be found in Bastion, 2 in Necrotic Wake, and 3 in Spires of Ascension.
Info from Wowhead
Use the HandyNotes: Shadowlands addon (you will need HandyNotes Addon plus HandyNotes: Shadowlands- both found on Curseforge) to see shards on map and to keep track of the shards you looted.
Wowhead user Zarillion has compiled coordinates for all shards.
You can use the Coordinates below with the TomTom addon to find them.
/way 39.05 77.04 Shard #01: On a lower platform below the bridge.
/way 43.63 76.22 Shard #02: On a ledge above the waterfall.
/way 48.42 72.73 Shard #03: On top of an arch halfway up the main structure.
/way 52.67 75.55 Shard #04: On a ledge just above the water.
/way 53.31 73.62 Shard #05: In the water beneath a small bridge.
/way 53.49 80.60 Shard #06: On top of a thin stone column.
/way 55.96 86.66 Shard #07: Above the entrance to the Chamber of First Reflection.
/way 61.04 85.66 Shard #08: On a rock in the side of the cliff.
/way 58.10 80.08 Shard #09: On a rock above a small waterfall.
/way 56.87 74.98 Shard #10: On the wall above a small water fixture.
/way 65.52 71.92 Shard #11: Hidden behind a stone column on the upper level of Purity’s Pinnacle.
/way 58.15 63.91 Shard #12: Sitting behind a staircase.
/way 54.00 59.70 Shard #13: Sitting beneath a small bell.
/way 46.70 65.95 Shard #14: On top of a fallen stone archway.
/way 50.68 56.14 Shard #15: On top of a small wooden structure.
/way 34.84 65.78 Shard #16: On a small ledge directly beneath Epistasia.
/way 51.67 48.02 Shard #17: On a small ledge on the underside of Hero’s Rest.
/way 47.08 49.23 Shard #18: On the ground under the platform.
/way 41.39 46.63 Shard #19: On a ledge above Dionae’s cave.
/way 40.04 59.12 Shard #20: On top of a stone pillar.
/way 38.52 53.26 Shard #21: On top of a tilted structure.
/way 57.64 55.67 Shard #22: Sitting at the base of a tree.
/way 65.25 42.88 Shard #23: In a bookcase on the upper platform.
/way 72.38 40.29 Shard #24: On a ledge directly below the jutting cliff.
/way 66.89 26.92 Shard #25: Hidden beneath the platform.
/way 57.55 38.27 Shard #26: In the Hall of Beasts behind some barrels.
/way 52.16 39.39 Shard #27: On top of a thin stone column.
/way 49.99 38.26 Shard #28: Underneath the bridge on a rock.
/way 48.48 34.91 Shard #29: On top of a thin stone column.
/way 56.72 28.84 Shard #30: On the corner of the table.
/way 56.20 17.31 Shard #31: On a ledge above the Memorial Offerings treasure.
/way 59.88 13.91 Shard #32: On a ledge way below the cliff top. Jump on the rock next to it or you will be ported back up.
/way 52.44 09.42 Shard #33: In a cave under Miri’s Chapel, behind some barrels.
/way 46.69 18.04 Shard #34: On a ledge under a rocky overhang, path to the south.
/way 44.94 28.45 Shard #35: At the end of a small rock ledge.
/way 42.30 24.02 Shard #36: On a ledge overlooking the path.
/way 37.10 24.68 Shard #37: On a ledge above the small waterfall.
/way 42.81 33.21 Shard #38: On the tip of a small ledge.
/way 42.71 39.40 Shard #39: On top of the gazebo.
/way 33.03 37.62 Shard #40: At the end of a narrow rock ledge.
/way 31.00 27.47 Shard #41: At the bottom of the pond by the feet of a statue.
/way 30.61 23.73 Shard #42: On top of the stone archway.
/way 24.64 22.98 Shard #43: On top of a thin stone column on the lower level.
/way 26.15 22.62 Shard #44: Hidden behind a stack of barrels.
/way 24.37 18.21 Shard #45: Behind Rector Kalliope in a bookshelf.
Necrotic Wake:
/way 52.50 88.60 Shard #46: Behind the large fallen bell.
/way 36.20 22.80 Shard #47: Behind a stone pillar.
Spires of Ascension (Gardens of Repose):
/way 46.60 53.10 Shard #48: Sitting behind a lounge chair.
/way 69.40 38.70 Shard #49: Hidden behind a large torch.
Spires of Ascension (Font of Fealty):
/way 49.80 46.90 Shard #50: On a ledge hanging over the central font.
None the Wiser Guild 