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.

When active, aura decreases fire damage done to you and your party.
Resist Fire is the Paladin's level 1 Defensive Aura with no prerequisite; it opens nothing. While it is the active aura, you and every ally in range gain fire resistance and a higher maximum fire resistance; when it is not active, the Paladin alone keeps half of the maximum-resistance bonus as a passive. Two numbers decide it: the resistance, +52% at level 1 and +131% at level 20, and the maximum, +1% a hard point.
| Level | Radius | Resist Fire: + |
|---|---|---|
| 1 | 10.67 yards | 52% |
| 2 | 12 yards | 66% |
| 3 | 13.33 yards | 76% |
| 4 | 14.67 yards | 85% |
| 5 | 16 yards | 92% |
| 6 | 17.33 yards | 98% |
| 7 | 18.67 yards | 102% |
| 8 | 20 yards | 106% |
| 9 | 21.33 yards | 110% |
| 10 | 22.67 yards | 113% |
| 11 | 24 yards | 116% |
| 12 | 25.33 yards | 118% |
| 13 | 26.67 yards | 121% |
| 14 | 28 yards | 123% |
| 15 | 29.33 yards | 124% |
| 16 | 30.67 yards | 127% |
| 17 | 32 yards | 128% |
| 18 | 33.33 yards | 129% |
| 19 | 34.67 yards | 130% |
| 20 | 36 yards | 131% |
| 21 | 37.33 yards | 132% |
| 22 | 38.67 yards | 133% |
| 23 | 40 yards | 135% |
| 24 | 41.33 yards | 136% |
| 25 | 42.67 yards | 136% |
| 26 | 44 yards | 137% |
| 27 | 45.33 yards | 138% |
| 28 | 46.67 yards | 138% |
| 29 | 48 yards | 139% |
| 30 | 49.33 yards | 139% |
The resistance is the row's dm34, a diminishing curve from Param3 35 ("Resistance % Min") towards Param4 150 ("Resistance % Max"). The Basin writes it out:
fire resistance % = min(35 + [115 × [110 × lvl ÷ (lvl + 6)] ÷ 100], 150)
It reads +52% at level 1, +92% at 5, +113% at 10, +124% at 15, +131% at 20 and +139% at 30; the Basin's table only reaches the 150 cap at level 60. The radius is Param1 16 plus Param2 2 a level, times two thirds: 10 2/3 yards at level 1 and 36 at 20. The aura costs no mana. Both of those lines read lvl, so +skills and the level of an Aura When Equipped item count.
The two maximum-resistance lines read hard points only: the aura's second stat is maxfireresist at skill('Resist Fire'.blvl), +1% maximum fire resistance per hard point for everyone in range while the aura is active, and the passive (passivecalc1, skill('Resist Fire'.blvl)/2) is +1% per two hard points for the Paladin alone. Neither grows with +skills, so they are not in the table above.
Resist Fire is an aura with the row's resistfire state on the caster and on every ally in range, refreshed every two seconds (perdelay 50). It has no hit check and no damage. Its stats are fireresist at dm34 and maxfireresist at the hard-point count; they are added to the Fire Resist and Maximum Fire Resist you already have, and the sum is still bound by the cap on Resistances and Immunities, which is why the maximum line matters at all.
The Basin's page gives the rule for the passive: it does not apply while the aura is active. Its example is base level 10: +5% maximum fire resistance to the Paladin while the aura is off, +10% to the Paladin and his allies in range while it is on.
The resistance line is the easy part; past the cap it is wasted. The maximum line is the one that no item resistance can replace, and it only counts hard points.
The Basin lists the current game's Flickering Flame helm as an aura-when-equipped source at level 4–8; that supplies the lvl lines only, since an item's aura has no hard points.
No synergies: Resist Fire has no dsc3 lines and no …SymPerCalc column. It feeds two skills, both read as hard points (blvl):
Its own resistance and radius read lvl; its maximum-resistance lines read blvl.
Resist Fire deals no damage and is applied only to you and your party, so the player-versus-player rule has nothing to act on; 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