Unless stated otherwise, everything here is Diablo II: Resurrected build 3.3.93847, Reign of the Warlock.
Unless stated otherwise, everything here is Diablo II: Resurrected build 3.3.93847, Reign of the Warlock.

Passive: increases walk and run speed.
Increased Speed is a Barbarian Mastery (level 24, requires Increased Stamina, passive, no mana). It raises your run and walk speed by a percentage that climbs fast at first and then flattens: +13% at level 1, +28% at level 5, +43% at level 20, never more than +50%. The curve is the whole story of the skill. The first few points buy most of the bonus; the last ten buy a few percent.
| Level | Run/Walk Speed: + |
|---|---|
| 1 | 13% |
| 2 | 18% |
| 3 | 22% |
| 4 | 25% |
| 5 | 28% |
| 6 | 30% |
| 7 | 32% |
| 8 | 33% |
| 9 | 35% |
| 10 | 36% |
| 11 | 37% |
| 12 | 38% |
| 13 | 39% |
| 14 | 40% |
| 15 | 40% |
| 16 | 41% |
| 17 | 41% |
| 18 | 42% |
| 19 | 42% |
| 20 | 43% |
| 21 | 43% |
| 22 | 43% |
| 23 | 44% |
| 24 | 44% |
| 25 | 44% |
| 26 | 45% |
| 27 | 45% |
| 28 | 45% |
| 29 | 46% |
| 30 | 46% |
The bonus is passivecalc1 dm12, a diminishing-returns curve from skills.txt Param1 (7, "Velocity %") toward Param2 (50, "Velocity % per level" in the table's comment, though the column is the ceiling the curve approaches): +13% at level 1, +28% at level 5, +36% at level 10, +40% at level 15, +43% at level 20, +44% at level 25, +46% at level 30. The Basin's page writes it as min(7 + [43 × [(110 × slvl) ÷ (slvl + 6)] ÷ 100], 50) and its table only reaches the 50 at level 60. The line reads lvl, so +skills from items count, but on this curve a +skill at level 20 is worth less than one percent. There is no mana and no duration.
The bonus is applied through the row's passive stat velocitypercent whenever the skill has at least one point. It is the same stat that Faster Run/Walk on boots and charms raises, so it joins those as one more source of run and walk speed and feeds the same movement calculation; the Basin's page adds nothing about how it combines beyond naming the stat. It changes walking and running only: attack speed, cast speed and the speed of Leap or Whirlwind are not movement speed. It does not change the stamina drain of running, which is why the skill sits behind Increased Stamina in the tree.
Half the bonus a level 20 skill gives is already there at level 5: the curve is front-loaded, and the ceiling of 50 is not reached before level 60.
No synergies: Increased Speed has no dsc3 line and no synergy calc, nothing feeds it and it feeds nothing. Its one line reads lvl, so a +skill from an item counts, but on the diminishing curve the value of each extra level shrinks: 15 points for the first five levels, 15 for the next fifteen, 3 for the ten after that. The Basin's page says +1–3 Increased Speed can spawn on a primal helm of item level 25 or higher.
Increased Speed never touches a player; it changes only how fast the Barbarian walks and runs, and there is nothing for the player-versus-player damage rule to cut, see Player versus Player.
Written from the game's tables (build 3.3.93847) and the cited pages; a per-level table is computed from skills.txt and skilldesc.txt by the same evaluator the skill pages use. A “legacy rule” is a published engine rule no table proves; a “game table” is read from the table named. · Report incorrect data