The deadly shard is used to make the support cape and support hood. They are occasionally obtained by players with 99 Slayer when training Slayer. When combined with the Daemonheim shard (Dungeoneering), agile shard (Agility) and hidden shard (Thieving), it will turn into the support cape and hood. The cape has the same bonuses as other Capes of Accomplishment but it comes with a different emote and boosts all relevant skills to 100 when operated. Deadly shards may be obtained from killing monsters from a slayer contract.
If you do not have space in your inventory, you'll get the message: "You found a shard emanating magical energy as you were training, but there was no space in your inventory to take it." Once there is a free space, the shard will be obtained.
If a player owns the expert skillcape shard bag, the shard will automatically be added to that bag, even if it is in the bank.