We're guaranteed to get the Steel DLC because of this:
>https://www.kickstarter.com/projects/11662585/hollow-knight/posts/1801455
>One Backer boss in particular has become a major rival character to Hornet, a mysterious Assassin Bug submitted by Jaspal Boodram. Jaspal’s assassin uses its proboscis as both a blade and a whip. We don’t want to spoil the surprises around this deadly foe, but expect several encounters throughout Hornet’s journey.
Sharpe is a backer boss who, among with his buddies, they cut last minute from Silksong.

Which means whatever the Steel Assassin shit is will be the next DLC for sure.