1) He is great card, statwise comparable to all your mentioned cards - except he is 3*
2) His price wont stay at current level forever. It will be more expensive and it will happen pretty soon.
+1 what Deepend is saying. Replace your Endo with it.
If you wan 4 or 5 stars, you will have to change Yusuke and Yu Mei with 2* cards like Muntendon, Chan, or Kusuri
getting Futoshi Ld is also a good idea when he's available, he's a solid 4*
Timber should be replaced imho, since you're not really going for OHKOs with that deck, especially in ELO. Ambre would be better in tourneys most of the time, or you should get Sung Tsu for that OHKO threat in tourneys.
2nd Macumba (attack aid is always needed) 3rd Zinfrid (Punch trough DR's = very desirable) - For ELO you'll want to have Kusuri and Chan because they are star-cheap. Also Windy Mor with his SoB and cheap price could be used as temporary patch if you are low on money. Throw away Timber, Endo and Yu Mei.
Kati is not that hot card, SoA is much needed but the delivery stats (7/4) are simply bad for 4* card. Linda is OK but vulnerable and the 1HKO potential is mostly not there, Sung Tsu is kind of insurance card agaist SoA clans but you dont need insurance against SoA clans because Pi Fang has anyway better base power = upper hand than SoA clans...
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