Call to Arms ability: Gives nearby Monkeys +50% attack speed and pops for a short time
~ BTD6 description
Call To Arms is the fourth upgrade of Path 2 for the Monkey Village in Bloons TD 6. It grants a special ability that when activated increases the attack speed and pierce by +50% for all towers in the Village's radius for 12 seconds, with a 45 second cooldown. Its attack speed and pierce bonuses granted by the Call To Arms ability are less than that for BTD5's M.I.B. Call to Arms ability, but the ability lasts longer and has a shorter cooldown.
Call To Arms, although not necessarily the most useful upgrade, is still a relatively viable option as a quick emergency ability in case nearby defenses are struggling. As it is the upgrade after Monkey Intelligence Bureau, it is not too difficult to access Call To Arms, because most of the time when this upgrade will shine the greatest is where there is a dense group of nearby powerful towers within range of the Village. Certain combos may especially benefit from Call To Arms, particularly any strong towers within range that are paired with other attack buffs such as Stronger Stimulant, Overclock, or Pat Fusty's Rallying Roar.
Do note that while it is very powerful on paper; in practice it can be hard to find the budget for Call to Arms in strategies and faces strong competition from other support and buffs. Its low uptime also hurts it immensely as it is not able to keep up its buffs over time.
Use it as an emergency ability for difficult rounds such as Rounds 95, 96, 98, or 99, where there are bound to be a lot of issues for towers with relatively low pierce and/or attack speed.
Call To Arms forms a decent synergy with Sentry Champion sentries. For Sentry Champion, activating the Call To Arms ability increases production speed of the sentries, sentry attack speed, and sentry pierce.
Amplifying the overall damage output with Pat Fusty's Rallying Roar ability is very useful in combination with towers that strongly benefit from the Call To Arms buff. If possible, try to synchronize Pat Fusty's Rallying Roar ability with the Call To Arms ability; in fact, their cooldowns are both 45 seconds by default, making it easier to combine their buffs.
Generally speaking, a 2-4-0 Call To Arms is better than a 0-4-2, because the extended Village range can allow more towers to become buffed. 0-4-2 Call To Arms might be necessary if using a multiple Monkey Commerces strategy while selling is disabled, however.
Call To Arms fulfills a range-based emergency support but it is expensive for its cost, and with other cheaper more cost-effective support options out there, Call To Arms tends to be outclassed in its role as support. The cost of Call To Arms was decreased, and later the Call To Arms ability cooldown was reduced and duration slightly increased, allowing it to be more useful in emergency situations.
Call To Arms cost decreased ($24,000 → $20,000).
Call to Arms has never had enough uptime for the small amount of space that it benefits.
~ Ninja Kiwi
Call To Arms cooldown reduced (60s → 45s).
Call to Arms didn't last enough in some critical situations where it could have made the difference, so this duration has been increased slightly.
~ Ninja Kiwi
Call to Arms duration increased (10s → 12s).
Description changed from "Call To Arms Ability: Gives all nearby Monkeys +50% attack speed and pops for 10 seconds." to current description
When activating Call To Arms Ability:
[Synchronized drum hitting and sword drawing]
Call To Arms Crosspaths (Top: Path 1, Bottom: Path 3)
On initial release until Version 8.0, Call To Arms upgrade was more expensive than the Tech Terror upgrade in BTD6 than in BTD5.
Since Version 8.0, where the Call To Arms upgrade received a price buff, the upgrade cost for Call To Arms on Medium is exactly the same as the amount of XP required to unlock this upgrade alone.
In BTD5, the M.I.B. Call to Arms upgrade gives +100% pierce and +100% attack speed, which is more than the bonus that Call To Arms gives. However, in BTD6, the ability lasts longer and has a shorter cooldown. (Ability in BTD6 lasts for 12 seconds and has a cooldown of 45 seconds.)