The file you're looking for is S_DropItem.ini.
But lets start at the beginning, first of all you have to take a look at the Eidolon in S_Partner.ini (we'll be using Merrilee in this example):
Code:
3|P00002|M670011|啟源聖女|夏娃|4|10|99|如你心中擁有堅定信念，美麗動人的夏娃將會守護著你，幫助夥伴是她的快樂泉源，對外表相當在意的她非常注重頭髮的保養，只要髮質有些許毛躁就會性情大變…她手中所持的魔杖【創世伊甸】能聚集冰雪元素並凝結成寒晶侵襲敵人，魔法與情感交融昇華而創造出的情愛之盾能夠治癒夥伴，是位全能的女魔法師。|25|s00631|2|5|2|5|2|2|2|6|3|6|3|2|5|7|6|7|5|4|6|8|7|8|6|5|11045|30|11179|1|||||11179|1|40201|1|||||40782|1|||||||54004|54005|54006|||2000|59021|59023|10|59025|59026|59027|||10|59028|59031|59032|59024|59029|59030|s13051|[COLOR=#ff0000]10002[/COLOR]|[COLOR=#ff0000]10002[/COLOR]|[COLOR=#ff0000]10002[/COLOR]|[COLOR=#ff0000]10002[/COLOR]|[COLOR=#ff0000]10002[/COLOR]|[COLOR=#ff0000]10002[/COLOR]|[COLOR=#ff0000]10002[/COLOR]|[COLOR=#ff0000]10002[/COLOR]|[COLOR=#ff0000]10002[/COLOR]|[COLOR=#ff0000]10002[/COLOR]||M670021||M672011|M602011||||3117|3104|3128|3143|54839|35004|35005|35006|45002|130|4|
I've marked a bunch of numbers in red (it's the same number multiple times), those are your drop IDs, so keep them in mind.
Using this info, you can now open S_DropItem.ini. There is an entry for the drop ID from above:
Code:
10002|夏娃|1||||1|0||11179|英雄徽記|1|5|60008|未鑑定的徽記寶箱(限定)|1|20|11047|源神經驗結晶(大)|2|43|11048|源神經驗結晶(完美)|1|29|15325|源神系列抽牌包|1|2|24810|源神雕像．夏娃|1|1|||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||
You're not able to receive gifts from some Eidolons because they are missing this entry.
To fix the issue, you have to get the ID from your target Eidolon and create a new drop entry for that ID.
