How to Play Ossiarch Bonereapers in Warhammer Age of Sigmar (4th Edition)

The army's defining battle trait is Relentless Discipline, a points-based resource system that gives Bonereapers a command-economy feel on top of the core game's command points.

• At the start of each battle round you generate a pool of Relentless Discipline points from your Heroes. Bigger, more important characters produce more points (widely reported examples include Katakros generating the most, mounted/chariot Liege-Kavalos a moderate amount, and spellcasting Mortisans a small amount).
• Throughout the round you spend those points on Relentless Discipline abilities that trigger in the movement, charge, and combat phases. Reported abilities include extra Move (Remorseless March), retreating and still charging (Impassive Retreat), lowering enemy Ward saves (Ruthless Extermination), +1 to wound (Pitiless Assault), and gaining a 5+ Ward (Inviolate Legions), plus anti-charge Rend.
• Most abilities cost a small number of points, with larger (reinforced) units costing more. Any unspent points are lost at the end of the round, so the trait rewards planning your whole turn around your pool.

The practical effect: you decide each round whether to lean into movement, offence, or durability. Exact point generation, ability names, costs, and ranges should be checked against your current Battletome, as these details are the most likely to be errata'd.

In 4th edition you pick one battle formation during army construction. Ossiarch Bonereapers have four confirmed formations, each nudging a different part of the roster. None is a hard "build-around", so pick the one that matches the core of your list.

• Mortisan Council - buffs your infantry Wizards/Mortisans (reported as +1 to casting). The most universally useful pick, since most lists run at least one Mortisan.
• Mortek Phalanx - lets a destroyed Mortek Guard unit come back (reported as returning at half strength on a roll). Rewards a horde-of-Guard style.
• Mortek Ballistari - specifically boosts Mortek Crawler artillery (reported as +1 to hit when static and in your own territory, for a limited number of Crawlers). For gunline lists.
• Kavalos Lance - gives your Cavalry a pre-game move (reported as up to 6"), useful for getting Deathriders or a mounted Hero up the board early.

Verify the exact wording, unit counts, and any restrictions in your current Battletome before committing.

• Mortek Guard - the core battleline block. Cheap, disciplined bodies that hold objectives and turn nasty when fed Relentless Discipline abilities. The backbone of almost every list.
• Kavalos Deathriders - fast(er) cavalry for objective grabs, flanking, and applying pressure the foot army can't.
• Immortis Guard / elite constructs - durable bodyguards for your key Heroes, keeping your points-generators alive.
• Necropolis Stalkers - flexible elite hitters that can adapt their attacks; a strong damage-dealing unit.
• Morghast Archai / Harbingers - big, resilient elite models; Harbingers hit hard on the charge, Archai are the tankier bodyguard variant.
• Mortek Crawler - the army's main ranged threat and a solid damage source this edition.
• Gothizzar Harvester - a healing/support engine that helps constructs recover, reinforcing the grind-them-down identity.
• Mortisan Heroes (Boneshaper, Soulmason, Soulreaper) - your casters and support characters; they also feed the Relentless Discipline economy.
• Named leaders (Katakros, Arch-Kavalos Zandtos, Liege-Kavalos) and Nagash - centrepiece Heroes that generate the most discipline points and provide powerful command-style effects; Katakros in particular anchors many lists.

Ossiarch Bonereapers are an attrition and control army. You are generally slower than your opponent, so you win by being impossible to shift and by out-grinding them over the game.

• Plan the whole round around your points. Because unspent Relentless Discipline points evaporate, decide up front which units will move, charge, or fight with buffs, and sequence your phases to spend efficiently.
• Protect your generators. Your Heroes fuel the entire engine, so screen them with Mortek Guard and bodyguard constructs and don't over-extend them.
• Hold the middle. Use resilient infantry and healing (Gothizzar Harvester, unit-return effects) to plant yourself on objectives and refuse to break.
• Pick your moment to swing offensive. Save points for a decisive combat where +1 to wound, anti-Ward, or a fight-again effect turns a grind into a kill.
• Use cavalry and elites for tempo. Deathriders and Stalkers/Morghasts give you the reach to contest what the foot slog can't.

• Wasting Relentless Discipline points. New players routinely leave points unspent or spend them reactively. Budget them like command points across the whole round.
• Over-committing your Heroes. Losing a big points-generator early cripples your economy for the rest of the game. Keep them screened.
• Playing too aggressively. The army is slow and durable, not fast and killy - if you race forward you lose your defensive advantage and get picked apart.
• Ignoring board control. Bonereapers win on objectives and attrition; forgetting to spread out and score is a classic loss.

Where they struggle: highly mobile armies that can dodge the slow advance and win on tempo, and elite alpha-strike lists that can burst down a key Hero before its points matter. Sustained shooting or high-Rend output can also chew through construct blocks faster than you can heal or return them.