Spell Focus

In standard NWN, the Spell Focus feats do one thing: +1 to the save DC of spells from that school. In Wyrdwood they also scale the spell's damage and raise its damage-dice cap, which is what makes focusing a school worth the three feat slots at epic levels.

What each tier gives

Feat	Save DC	Damage
Spell Focus	+1	+5%
Greater Spell Focus	+1	+10 to the damage-dice cap — or +10% damage on spells whose cap is already 60
Epic Spell Focus	+1	+25%

All three stack. A fully focused school is +3 DC, +30% damage and +10 dice.

The dice cap is the ceiling on how far a spell's damage grows with caster level. Most damaging spells roll one die per caster level up to a cap set per spell (20, 40, 50 or 60); Greater Spell Focus pushes that ceiling up by 10, so ten more caster levels count. On spells already capped at 60 there is nothing left to raise, so it pays out as flat damage instead.

Metamagic interaction

The percentage bonus applies to an ordinary cast. Maximize Spell and Empower Spell replace it — those two set the damage themselves, and the focus percentage is not added on top. The dice-cap increase from Greater Spell Focus applies either way, so a maximized spell still benefits from it.

Spells with their own upgrade

A handful of spells read your focus directly rather than just taking the percentage:

• Magic Missile — Greater Spell Focus (Evocation) upgrades every missile's damage die.
• Flame Arrow — Greater Spell Focus (Evocation) sharply increases each arrow's damage.
• Death Armor — Spell Focus (Necromancy) doubles the bonus damage die, and Greater / Epic Spell Focus raise how far the shield's damage scales with caster level (10 → 15 → 20).
• Ethereal Visage — Spell Focus (Illusion) adds to its damage reduction, and Epic Spell Focus raises the reduction's power.

Which school a spell belongs to

Schools are read from the spell tables, so a spell's school is whatever the toolset and your character sheet say it is. A few abilities — notably the Duskblade's Arcane Channelings and other class powers cast as spells — belong to no school at all, and no Spell Focus feat affects them.

Alertness

Alertness grants what it says it grants and nothing more. For a long stretch it was quietly standing in for all three Spell Focus tiers at once — +30% damage and +10 dice on every damaging spell (+40% on spells already capped at 60) — while the Spell Focus feats themselves added nothing. Both halves of that are now fixed: expect some monster casters to hit noticeably softer, and your focused school to hit harder.