Redspines are elite mooks with high health and strong attacks that possess the ability to throw javelins, which are used to soften soldiers before going in for the kill rather than as a primary attack. Redspines are otherwise fairly durable and not very easy to kill (even at later waves), and, alongside Greenfins and Deviltides, serve mostly to quickly get through towers and reduce lives while the Blacksurges and Bluegales mostly concern themselves with crippling your defenses.
Their ranged attack deals 100-130 physical damage.
Redspines supposedly have a very high physical armor rating, but this is actually not true, meaning that it's okay to use Archer Towers against them. However, make them as high-level as possible, as they have quite a lot of HP. When not blocked, they throw spears to your units every 3 seconds and can deal a fatal blow to unarmored heroes with just a few attacks. So, it's recommended to stall them with Reinforcements and armored heroes. If you really wish to use Barracks troops against them, go for Templars or Assassins. Redspines, in addition to their toughness, deal heavy damage with each attack. With the Templars' high HP and medium armor, they can mitigate a Redspine's heavily damaging attack, whereas Assassins can conceal themselves until the Redspine is in melee range.