Xenosaga Episode I Reference

Ether

Ether is the game's healing, support, status, and spell system. Spend E.Pts to evolve native ability trees or transfer an eligible Ether, then use Set to place the abilities you need within the character's 12-point Ether weight limit.

Learn, transfer, and Set

No.	Action
1	Open Use E.Pts and inspect the character's native evolution tree. Evolving an Ether opens the next branch shown by the menu.
2	Transfer broadly useful eligible Ether to the characters who need it. The transfer costs half the displayed evolution E.Pts, and the original character keeps the ability.
3	Use Set. Learned and transferred Ether do not appear in battle until equipped.
4	Keep the combined Ether weight at 12 or less. A powerful ability can consume most or all of the available weight by itself.
5	Before a boss, replace general exploration abilities with the healing, status clearing, stealing, buff, or elemental attack the fight actually rewards.

Using Ether in battle costs 4 AP plus the ability's EP cost. Native-only abilities remain exclusive to their original user; the complete character tables mark them directly.

Fast Ether decisions

Need	Start here
Basic healing on another character	Evolve and transfer Medica early. Life Shot is a stronger single-target alternative from MOMO's tree.
Heal the whole party	Medica All provides medium recovery. Healing Dew costs less EP but provides lower recovery.
Clear status effects	Refresh clears one ally. Purifying Storm clears the whole party.
Revive an ally	Refine provides low recovery, Revert provides medium recovery, and Best Ally is chaos' native-only full-party emergency recovery.
Control the turn order	Boost 1 grants a Boost level, while Quick and Speed Medicine increase one ally's speed.
Steal an item	Psycho Pocket is the clean transferable choice. Queen's Kiss is Shion-only and can also inflict Instant KO.
Stop enemy Ether	Misty disables a Biological or Gnosis enemy's Ether. Down Ether lowers Ether attack and defense for a valid target.
Exploit an elemental weakness	KOS-MOS has all-enemy Fire, Ice, and Lightning attacks. chaos has single-target Fire, Ice, and Lightning attacks.
One large endgame attack	Erde Kaiser deals 9,999 damage to all enemies but costs 60 EP, uses all 12 Ether weight, and is limited to once per battle.

Native evolution paths

Character	How the tree develops
Shion	Medica branches through Analyze and Goodbye. The healing and support branches lead to Medica All, Refresh, Boost 1, Jamming, Medica Rest, Revert, Safety Level, Quick, and Queen’s Kiss. Robot Part attacks are earned separately.
KOS-MOS	Mode A7 branches into Down Dex and Down Force. Those lead to Down Ether, Gate, Ether Limit, Satellite, and the three all-enemy Dex Ether attacks.
Ziggy	My Guard branches into Bodyguard and Recharge. Those paths lead to Ether Shift A, Ether Shift B, Charge X, Red Mark, and Speed Boost.
MOMO	Life Shot branches into Miracle Star and Sheep Beam, then Prayer, Refine, and Junk Beam. Star Wind and Starlight are separate transformation trees with their own abilities.
chaos	Protective Armor branches into Healing Dew and Ice Wings. Those paths lead to Purifying Storm, Best Ally, Flame Wings, Lightning Wings, Supreme Judgement, Cataclysm, and Light & Wings.
Jr.	Psycho Arm branches into Ether Flare and Dandyism, then Psycho Pocket, Chain, Misty, Coin Lock, and Speed Medicine. Magnum Joe and Buster Joe form a separate summon path.

Complete character lists

These are native-user lists, not transfer restrictions. Rows explicitly marked native-only are the abilities that cannot be passed to another character.

Shion

Name	Effect and transfer restriction
Analyze	Displays combat and reward information for one enemy.
Boost 1	Adds one Boost level to one ally.
Dominion Tank	One-use-per-battle attack against all enemies, earned from both Robot Legs. Native-only; cannot be transferred.
Erde Kaiser	One-use-per-battle 9,999-damage attack against all enemies, earned after completing the Robot Part quest. Native-only; cannot be transferred.
Goodbye	Makes one ally escape an eligible battle.
Jamming	Lowers one Mechanical enemy's Dexterity.
Medica	Low HP recovery for one ally or enemy.
Medica All	Medium HP recovery for all allies.
Medica Rest	High HP recovery for one ally or enemy.
Queen's Kiss	Steals from one enemy and can inflict Instant KO. Native-only; cannot be transferred.
Quick	Increases one ally's speed by 25 percent.
Refresh	Removes status effects from one ally.
Revert	Revives one ally with medium HP recovery.
Safety Level	Lets one ally survive a finishing blow with 1 HP.
Seraphim Bird	One-use-per-battle attack against all enemies, earned from the Robot Part Head. Native-only; cannot be transferred.
Throni Blade	One-use-per-battle slash attack against all enemies, earned from both Robot Arms. Native-only; cannot be transferred.

KOS-MOS

Name	Effect and transfer restriction
Dex Ether Fa	Fire Ether attack against all enemies.
Dex Ether Le	Lightning Ether attack against all enemies.
Dex Ether Ra	Ice Ether attack against all enemies.
Down Dex	Lowers one target's Dexterity.
Down Ether	Lowers one target's Ether attack and defense.
Down Force	Lowers one target's physical attack.
Ether Limit	Doubles KOS-MOS's Ether damage and EP cost.
Gate	Deals one-quarter maximum HP and can inflict Instant KO on one target.
Mode A7	Applies Focus Physical Attack to KOS-MOS.
Satellite	One-use-per-battle Beam attack against all enemies. Native-only; cannot be transferred.

Ziggy

Name	Effect and transfer restriction
Bodyguard	Raises Ziggy's strength and defense while MOMO is behind him. Native-only; cannot be transferred.
Charge X	Once per battle, doubles HP and EP recovery received.
Ether Shift A	Raises Ziggy's Ether defense while lowering Ether attack.
Ether Shift B	Raises Ziggy's Ether attack while lowering Ether defense.
My Guard	Raises Ziggy's physical defense while lowering physical attack.
Recharge	Restores a medium amount of Ziggy's HP.
Red Mark	Once per battle, raises critical-hit chance against one Mechanical target.
Speed Boost	Raises Ziggy's speed by 50 percent.

MOMO

Name	Effect and transfer restriction
Junk Beam	Inflicts Junk Heap on one Mechanical enemy.
Life Shot	Medium HP recovery for one ally or enemy.
Miracle Star	Non-elemental Ether attack against one enemy.
Prayer	Produces a random item during battle.
Refine	Revives one ally with low HP recovery.
Sheep Beam	Puts one Mechanical enemy's pilot to sleep.
Star Action	Star Wind-only Ether that fills one ally's AP. Native-only; cannot be transferred.
Star Bell	Starlight-only non-elemental Ether attack against one enemy. Native-only; cannot be transferred.
Star Bunnie	Starlight-only non-elemental Ether attack against all enemies. Native-only; cannot be transferred.
Star Veil	Star Wind-only Ether that reduces Ether effects for all allies. Native-only; cannot be transferred.
Star Wind	Once per battle, transforms MOMO into Star Wind form. Native-only; cannot be transferred.
Starlight	Once per battle, transforms MOMO into Starlight form. Native-only; cannot be transferred.

chaos

Name	Effect and transfer restriction
Best Ally	One-use-per-battle full-party revive and recovery Ether. Native-only; cannot be transferred.
Cataclysm	Resets attack and wait time for all enemies.
Flame Wings	Fire Ether attack against one enemy.
Healing Dew	Low HP recovery for all allies.
Ice Wings	Ice Ether attack against one enemy.
Light & Wings	Attacks all enemies and clears their status effects.
Lightning Wings	Lightning Ether attack against one enemy.
Protective Armor	Reduces Ether attack effectiveness against one target.
Purifying Storm	Removes status effects from all allies.
Supreme Judgement	Halves one enemy's HP recovery.

Jr.

Name	Effect and transfer restriction
Buster Joe	One-use-per-battle Great Joe summon against all enemies. Native-only; cannot be transferred.
Chain	Lowers one enemy's evasion.
Coin Lock	Blocks all status changes on one ally.
Dandyism	Revives Jr. after KO when a female character is in the rearguard. Native-only; cannot be transferred.
Ether Flare	Raises Ether effectiveness for one ally or enemy.
Magnum Joe	One-use-per-battle Great Joe summon against one enemy. Native-only; cannot be transferred.
Misty	Disables one Biological or Gnosis enemy's Ether.
Psycho Arm	Raises Jr.'s physical attack.
Psycho Pocket	Steals an item from one enemy.
Speed Medicine	Raises one ally's speed by 25 percent.

For EP-saving equipment and extracted passive abilities, see Character Equipment and Skills. The complete Robot Part route for Erde Kaiser is on Robot Parts and Erde Kaiser.