starting out dont dont shards as you get them as hard as it will be
store them until you get to a 2x sacred event - this means the chance doubles for each sacred shard you drop to pull a legendary champ. Void shards have the worst % legendary drop rate so definately store a few of them up before pulling.
id like to see voids during 2x being 5x as 1% isnt flash and the number of rares you get is crazy