The Essence Tree
The Essence Tree is Marrow March’s permanent upgrade tree, and it grows only when the wall falls: a fall ends the run and opens the tree, and the Essence you earned is spent there. It holds 100 upgrades in 205 steps across 6 disciplines. No step has more than five levels, each is revealed when the one before it is bought, and some deeper steps are paid in diamonds from the Colossi; the tree is whole without them. Grow every step and the tree’s heart opens onto the Ancestral Sky.
Warfare (14) · Stronghold (34) · Commerce (12) · Doctrine (14) · Arcana (11) · Works (15)
Warfare
What your soldiers hit with: damage, attack speed, reach and critical hits. 14 upgrades.
| Upgrade | Effect | Levels | Steps |
|---|---|---|---|
| First Blood | +4% unit damage | 1 | 1 |
| Damage | +4% unit damage | 3 | 6 |
| Attack Speed | +2% attack rate | 5 | 2 |
| Range | +2% range | 5 | 1 |
| Double Shot | +1% archer double shot | 5 | 2 |
| Crit Chance | +1.5% crit chance | 3 | 2 |
| Piercing | +1 armour pierced | 2 | 1 |
| Crit Damage | +12% crit damage | 5 | 1 |
| Executioner (keystone) | Cull foes below 8% HP | 1 | 1 |
| Siege Crew | +3% blast radius | 5 | 4 |
| Gale Force | +4% push distance | 5 | 2 |
| Veteran Cadre | +4% veterancy gain | 5 | 4 |
| Giant Killer | +4% damage to a Colossus | 5 | 4 |
| Warlord (keystone) | Every 5th shot of a soldier is a critical hit | 1 | 1 |
Stronghold
The wall and the ground before it: wall strength, repairs, and the gatehouse once the road is yours. 34 upgrades.
| Upgrade | Effect | Levels | Steps |
|---|---|---|---|
| Mortar | +20% wall HP | 1 | 1 |
| Wall HP | +20% wall HP | 3 | 2 |
| Masonry | +3 HP per repair | 5 | 1 |
| Frontier | +1 deploy column | 1 | 3 |
| Quarry | -8% repair cost | 5 | 1 |
| Standing Garrison | +2 HP mended per assault | 5 | 1 |
| Wound Winches (with the Inner Ward) | -6.5% scorpion reload | 5 | 1 |
| Barbed Bolts (with the Inner Ward) | +1 foe a bolt goes through, +10% bolt damage | 5 | 1 |
| Forged Chains (with the Inner Ward) | +12% time the grate holds | 5 | 1 |
| Pitch and Tallow (with the Inner Ward) | +16% oil scald, +8% oil reach | 5 | 1 |
| Scouting | Reveals the coming assault | 1 | 2 |
| Reinforced Ramparts | +1% wall mitigation | 5 | 1 |
| Spike Pits | +4% spike salvage | 5 | 1 |
| Last Stand (keystone) | Faster while the wall fails | 1 | 1 |
| Mortar Lore | +1 Bone Mortar charge | 3 | 2 |
| Self-Mending Stone | +1% of the wall mended per assault | 5 | 2 |
| Iron Bands | +40% wall HP | 5 | 2 |
| Watchfires (keystone) | Scouts report each foe's health and armour | 1 | 1 |
| Bored Barrels | +6.5% wall gun damage | 5 | 6 |
| Drilled Crews | -3% wall gun cooldown | 5 | 4 |
| Raised Embrasures | +9.5% wall gun range | 5 | 1 |
| Through-Bolts | +1 foe a Springald bolt goes through | 3 | 1 |
| Iron Balls | +5% Ball Chute damage | 5 | 1 |
| Long Chute | +5% Ball Chute reach | 5 | 1 |
| Hotter Coals | +5% Cresset burn | 5 | 1 |
| Wide Bowl | +4% Cresset reach | 5 | 1 |
| Heavy Stones | +5% Trebuchet blast | 5 | 1 |
| Heavy Links (with the Inner Ward) | +5% the Chain holds | 5 | 1 |
| Whip Chain (with the Inner Ward) | +6% the Chain's snap | 5 | 1 |
| Wide Lash (with the Inner Ward) | +5% the snap's reach | 5 | 1 |
| Quick Windlass (with the Inner Ward) | -4% the Chain's rehang | 5 | 1 |
| Long Burn (with the Inner Ward) | +6% the oil burns longer | 5 | 1 |
| Pitch Masters (with the Inner Ward) | +5% Pitch Pot burn | 5 | 1 |
| The Wall Rallies (keystone) | Once a run, a falling wall rises again to 50% HP | 1 | 1 |
Commerce
Gold: what the dead pay, what a run starts with and what things cost. 12 upgrades.
| Upgrade | Effect | Levels | Steps |
|---|---|---|---|
| Tally Stick | +5% gold from kills | 1 | 1 |
| Gold Gain | +5% gold from kills | 3 | 6 |
| Starting Gold | +40 starting gold | 5 | 1 |
| Cheap Steel | -1.6% unit and upgrade cost | 5 | 3 |
| Salvage | +5% sell refund | 3 | 2 |
| Gilded Bones | +1% glittering spawn | 3 | 2 |
| Golden Harvest (keystone) | Every 100th kill pays 20x | 1 | 1 |
| Gold Teeth | +8% gold from a glittering foe | 5 | 4 |
| Spoils of War | +5% gold from a Colossus | 5 | 6 |
| The Foundry | -4.5% unit and upgrade cost | 5 | 2 |
| The Mint | +6% gold from kills | 5 | 2 |
| Strongbox (keystone) | Each assault held pays 5% interest on the gold you kept | 1 | 1 |
Doctrine
Running the siege: training, promotions, skills and the garrison. 14 upgrades.
| Upgrade | Effect | Levels | Steps |
|---|---|---|---|
| Resonance | +3% chant potency | 5 | 4 |
| Long Breath | +3% chant duration | 5 | 3 |
| Quicker Breath | -1.5% chant cooldown | 5 | 3 |
| Field Notes | -6% unit upgrade cost | 1 | 1 |
| Quartermaster | Shift-click buys +2 | 3 | 2 |
| Field Promotion | -2% promotion cost | 5 | 3 |
| Academy | -2% skill cost | 5 | 3 |
| Logistics | -1.8% unit upgrade cost | 5 | 3 |
| Standing Orders (keystone) | Mends the wall up to 25% each assault | 1 | 1 |
| Officers’ Mess | -5% promotion cost | 5 | 1 |
| Libraries | -5% skill cost | 5 | 1 |
| Armoury | -1% unit upgrade cost | 5 | 3 |
| Standing Masons (keystone) | Raises the mend floor another 25% | 1 | 1 |
| War College (keystone) | Every 5th training level of a soldier is free | 1 | 1 |
Arcana
Essence, artifacts and lasting effects. 11 upgrades.
| Upgrade | Effect | Levels | Steps |
|---|---|---|---|
| Lingering Flame | +4% status duration | 5 | 3 |
| Essence Flow | +4% essence earned | 5 | 3 |
| Reliquary | +5% diamonds from a Colossus | 5 | 4 |
| Grave Dust | +6% essence earned | 1 | 1 |
| Bone Lore | +6% essence earned | 5 | 2 |
| Sigil Craft | +5% diamonds from a Colossus | 5 | 4 |
| Gravebinding | +1% artifact chance | 5 | 3 |
| Ledger Rites | +5% essence | 5 | 4 |
| The Hourglass | +4% essence | 5 | 1 |
| Ember Ward | +4% status duration | 5 | 4 |
| Death’s Ledger (keystone) | A fall pays its essence in full | 1 | 1 |
Works
Traps and the guns on the wall. 15 upgrades.
| Upgrade | Effect | Levels | Steps |
|---|---|---|---|
| Sappers | +1.5% trap damage | 5 | 6 |
| Dug Ditch | The dead walk 5% slower | 1 | 1 |
| Spadework | +5% trap damage | 1 | 1 |
| Sharpened Stakes | +5% trap damage | 5 | 7 |
| Deep Set | +5.5% trap charges | 5 | 6 |
| Lingering Work | +20% hold, slow and strip duration | 5 | 2 |
| Salt and Rust | +2 armour stripped | 5 | 1 |
| Scavenged Iron | -8% rearm cost | 5 | 2 |
| Hair Trigger | -1 body needed to spring a charge | 3 | 1 |
| Barbed Spikes | +5% Spike Trench bite | 5 | 1 |
| Thick Tar | +4% Tar Spill slow | 5 | 1 |
| Iron Jaws | +5% Snare hold | 5 | 1 |
| Black Powder | +5% Powder Charge blast | 5 | 1 |
| Wide Kegs | +4% Powder Charge reach | 5 | 1 |
| Self-Setting Traps (keystone) | Rearming traps costs nothing | 1 | 1 |