Where do you buy weapons in Be The Final Boss?

Inside the WEAPONS panel — the same grid that lists every weapon by its DMG number. Selecting a weapon you do not own replaces the EQUIPPED button with its coin price, 5000000000 COINS for the Obsidian Executioner on camera, and the purchase happens there. The recording never shows which button opens the panel, and no separate weapon shop, vendor or NPC screen appears anywhere in it.

How much does the Obsidian Executioner cost?

5,000,000,000 Coins, and the frames show it actually being spent: the counter reads 5,000,419,640 on the price frame and 419,640 one second later with the weapon EQUIPPED. That is a Coin price, not a Robux price. Our weapons table separately records the Silverwind Glaive at 3,000,000,000 Coins from a different panel capture, so the billion-scale tier of the ladder starts below the Obsidian Executioner.

Is the Obsidian Executioner the best weapon in the game?

Unproven. It carries the highest damage bonus our weapons table publishes, +3400, and the frame agrees. But the same panel shows four further slots above it at DMG +4050, +4800, +5650 and +6600, all still locked silhouettes with no names on camera, so 'highest number we can read' is not 'highest in the game'. The S-D tiers on the weapons page are a third-party community ranking that weighs swing speed and upgrade cost, and this panel publishes neither — which is why Obsidian Kanabo outscores several C-tier weapons yet ranks D there.

Can you upgrade a weapon instead of buying the next one?

Not on this footage. Across every frame on this page the WEAPONS panel offers exactly two states — a coin price, or EQUIPPED — plus the ARMOR FORGE and BOSS ABILITIES tabs, and no level, star, +1/+2 or upgrade-cost control appears anywhere. Do not read the ARMOR FORGE tab as a weapon upgrade path: that is the armor and Forge Stone system, which the armor guide covers.

Be The Final Boss Weapons Guide: Where They Are Bought and What They Cost

An illustrated, frame-checked walkthrough of weapon buying in Be The Final Boss: the WEAPONS panel's damage ladder, the coin price printed on a locked weapon, and the parts of the decision the interface never tells you.

Quick answer

Weapons are bought inside the WEAPONS panel — one scrollable grid, four cards a row, sorted by the DMG number printed on each card. A weapon you already own shows a green EQUIPPED button; a weapon you do not own shows a blue coin price instead. On camera the Obsidian Executioner costs 5000000000 COINS for DAMAGE +3400, and the coin counter drops from 5,000,419,640 to 419,640 in the next second. The prices our table has recorded climb far faster than the damage does — +45 for 10 Coins early on, +435 for 500,000, +2,900 for 3,000,000,000 — and the panel publishes no attack speed, no DPS and no upgrade cost, so the only comparison the interface actually offers is DMG against the price in front of you.

Video source

Frames are from Liam Difu Reynoso's screen recording 'UNLOCKING THE OBSIDIAN EXECUTONER SWORD' (the misspelling is the creator's). It carries no usable narration — the auto-captions are music and sound effects only — so every number on this page is either legible on a frame we opened and read, or is labelled as coming from our own weapons table. The recording's upload date could not be retrieved this run, so this page does not date-stamp it; note that the panel it shows has a BOSS ABILITIES tab and four weapon slots above the Obsidian Executioner that the captures behind our weapons table never mention.

Liam Difu Reynoso — UNLOCKING THE OBSIDIAN EXECUTONER SWORD

Buying and choosing weapons, step by step

1
Open the WEAPONS panel and read the damage ladder
Weapons live in one panel titled WEAPONS. It is a grid, four cards to a row, ordered by the number printed on each card: DMG: +30 Iron Sword, DMG: +45 Steel Broadsword, DMG: +70 Reinforced Halberd, DMG: +90 Gilded Longsword, then Obsidian Kanabo +120, Glacial Greatsword +160, Colossal Morningstar +210 and Phantom Glaive +280. Three tabs sit under the grid — WEAPON, ARMOR FORGE and BOSS ABILITIES — and only WEAPON is opened on camera; the Forge belongs to the armor system. What this recording never shows is how the panel is first opened. No HUD button is clicked on screen, so treat the entry point as unverified rather than guessing at an icon.
The weapon list is one scrollable grid sorted by the DMG number printed on each card, so the cheapest entries come first.
2
Scroll the middle of the list before you spend anything
One page down the ladder continues: Hollowed Buster +350, Ironclad Morningstar +435, Cobalt Edge +520, Voidweaver Pincer +620, then four cards reading +720, +840, +960 and +1110 whose names are not legible in this capture. Our weapons table fills those four from other panel footage as Obsidian Cleaver, Vanguard Axe, Bloodbone Pike and Onyx Broadsword, in that order. The detail card open on screen at this moment belongs to the Infernal Greataxe: the rarity word SECRET, DAMAGE: +1930, and a green EQUIPPED button. That is the entire information budget of the interface — a name, a rarity word, one flat damage number. There is no attack speed, no DPS, no range and no upgrade cost anywhere on the panel.
Each card opens a detail panel with only a name, a rarity word and one flat damage bonus — no attack speed and no upgrade cost.
3
Select a locked weapon to see its real coin price
A weapon you do not own is a black silhouette, and selecting it replaces the green button with a blue price. On camera the Obsidian Executioner reads SECRET, DAMAGE: +3400, and 5000000000 COINS, while the coin counter in the HUD still reads 5,000,419,640. Two things come attached to that frame. The first is that the price is paid in Coins, the currency the run itself pays you, not Robux — this panel offers no Robux shortcut. The second is that the Obsidian Executioner is not the top of the list: the row beside it holds four more silhouettes reading DMG: +4050, +4800, +5650 and +6600, and the capture shows no name for any of them.
A weapon you do not own shows no artwork at all, and its button becomes the price you would have to pay.
4
Buy it and the button flips to EQUIPPED
One second later the same card has resolved into a blue obsidian blade, the button is green EQUIPPED, and the coin counter reads 419,640 — exactly 5,000,000,000 less than the previous frame, which is the only proof of the purchase the recording gives. No level requirement, no wave gate and no confirmation dialog appears between the two shots; they are one second apart, so anything that flashed in between is simply not on camera. Nothing in this footage shows a weapon being levelled, starred or upgraded. The panel only ever offers a price or an EQUIPPED state.
5,000,419,640 Coins before the click and 419,640 after — the purchase is exactly the 5,000,000,000 printed on the button.
5
Judge the swap in the field, not in the menu
With the new blade equipped the run goes on at wave 1102: each swing draws a wide horizontal blue arc across the courtyard, the banner above reads '4 left 0/4 Next Checkpoint: 1125' and 'Wave 1125: Crusader Champion', the player's own health bar sits at 4861330 / 4861330, and the Soul Rend ability slot at the bottom right reads READY. None of that tells you what the +3400 is worth. The footage never clears the same wave with two different weapons, so no damage number on this page converts into waves gained. The honest comparison stays the one the panel itself offers: DMG against the coin price in front of you.
In the field the blade draws a long horizontal arc; the wave banner, not the weapon menu, is what tells you how far you still have to go.