Child of Violence is an unfound Unique Small Cluster jewel datamined in 3.10 Delirium League. Secrets of its existence are still a mystery.
Child of Violence grants the Pitfighter keystone with a datamined modifier of '1% increased Fishing Line Strength'.
Months later in Jun 2020, GGG (seemingly accidentally) included the Pitfighter keystone in their Harvest Notables and cluster jewel rebalance info post. When spotted, Bex replied "Oops, better take that out" and Pitfighter was removed from the page.
There are a few possibilities for why Pitfighter was included on the Harvest Notables post:
Independently,mismatch was spotted in the number of Unique Items teased for Delirium compared to the number of unique items found by players.
The GGG Delirium patch notes stated: 'Added 16 new Unique Items, including one designed by one of our Supporters!'
This may merely be a mistake in patch notes, of course, which it seems has happened before.
GGG was contacted to get clarity on the discrepancy and hope we would get a simple confirmation that this discrepancy was merely an error in the patch notes and we could close the issue. Unfortunately, a reply from Support, after some pushing, agreed to escalate, but then returned with the stock reply "I'm afraid we're unable to speculate on this any further".
The "missing" item (if one even exists) may be a result of Child of Violence being cut after the patch notes were written, but before Delirium went live. Or perhaps Child of Violence truly is an extant overlooked item. Or perhaps there is some other undiscovered item.
The lore of Child of Violence and Pitfighter have flavour texts which refer to story surrounding characters in the Grand Arena. The Grand Arena is associated with historical figures such as Daresso and Barkhul.
Areas associated with this lore include:
Related lore: The official GGG Lord's Labyrinth Gamebook (written by Chris Kluwe / Loate) features a protagonist who is a gladiator / pitfighter.
During Delirium League, a Delirium Mirror spawned in every Story Area.
After Delirium League ended and Delirium went core, Delirium Mirrors only spawn after the player slays the Beast (thus freeing Tangmazu, the Strange Voice).
This means that it is no longer possible for Act 4 areas such as Daresso's Dream / The Grand Arena to be influenced by Delirium. Thus these Story Areas can likely be safely ignored.
If Child of Violence exists, most likely it must be obtained in an Endgame zone such as a Map or Simulacrum.
Similar to Angler's Plait, there may be multiple concurrent conditions which must be satisfied to enable a special drop.
As a random example, consider the Embrace Madness skill and its associated Glorious Madness debuff available from Beacon of Madness. This unusual debuff is Delirium-themed and therefore could be related. Any number of other esoteric conditions like this one might apply; without any confirmed Child of Violence drops, we have no concrete way of definitively narrowing down the possibility space.
Another observation is that the Pitfighter Keystone art itself depicts bloodied spiked armour. This may be a hint to Thorns (reflecting damage back to attackers) or Thorns-related Unique Items.
The only conclusive testing so far has been chancing with Trash to Treasure a Small Cluster Jewel in the following Areas:
This is not unexpected. It is very likely that if Child of Violence exists, it is likewise drop-restricted, and therefore impossible to obtain via Chance Orbs.
The further testing needs to keep in mind the following choices:
Due to lore's connection to Daresso and gladiators, maps with tags arena_area or pitfight_area seem the most likely candidates.
Due to pattern with Unique Small Cluster jewels - they only drop from Kosis and Omniphobia - it is expected that Child of Violence should drop from them as well.
Just like Angler's Plait requires Corrupted Slitherpinch, it is expected that Child of Violence has one as well.
More like, due to the amount of people playing poe, and due to Delirium being available as Zana mod in 3.12, there must be a specific gear or kill-way requirement in order to obtain Child of Violence (if Child of Violence does exist in game).